String

Class

A String object has an arbitrary sequence of bytes, typically representing text or binary data. A String object may be created using String::new or as literals.

String objects differ from Symbol objects in that Symbol objects are designed to be used as identifiers, instead of text or data.

You can create a String object explicitly with:

A string literal.
A string literal.

You can convert certain objects to Strings with:

Method String.

Some String methods modify self. Typically, a method whose name ends with ! modifies self and returns self; often a similarly named method (without the !) returns a new string.

In general, if there exist both bang and non-bang version of method, the bang! mutates and the non-bang! does not. However, a method without a bang can also mutate, such as String#replace.

Substitution Methods

These methods perform substitutions:

String#sub: One substitution (or none); returns a new string.
String#sub!: One substitution (or none); returns self.
String#gsub: Zero or more substitutions; returns a new string.
String#gsub!: Zero or more substitutions; returns self.

Each of these methods takes:

A first argument, pattern (string or regexp), that specifies the substring(s) to be replaced.
Either of these:
- A second argument, replacement (string or hash), that determines the replacing string.
- A block that will determine the replacing string.

The examples in this section mostly use methods String#sub and String#gsub; the principles illustrated apply to all four substitution methods.

Argument pattern

Argument pattern is commonly a regular expression:

s = 'hello'
s.sub(/[aeiou]/, '*')# => "h*llo"
s.gsub(/[aeiou]/, '*') # => "h*ll*"
s.gsub(/[aeiou]/, '')# => "hll"
s.sub(/ell/, 'al')   # => "halo"
s.gsub(/xyzzy/, '*') # => "hello"
'THX1138'.gsub(/\d+/, '00') # => "THX00"

When pattern is a string, all its characters are treated as ordinary characters (not as regexp special characters):

'THX1138'.gsub('\d+', '00') # => "THX1138"

String replacement

If replacement is a string, that string will determine the replacing string that is to be substituted for the matched text.

Each of the examples above uses a simple string as the replacing string.

String replacement may contain back-references to the pattern’s captures:

\n (n a non-negative integer) refers to $n.
\k<name> refers to the named capture name.

See Regexp for details.

Note that within the string replacement, a character combination such as $& is treated as ordinary text, and not as a special match variable. However, you may refer to some special match variables using these combinations:

\& and \0 correspond to $&, which contains the complete matched text.
\' corresponds to $', which contains string after match.
\` corresponds to $`, which contains string before match.
\+ corresponds to $+, which contains last capture group.

See Regexp for details.

Note that \\ is interpreted as an escape, i.e., a single backslash.

Note also that a string literal consumes backslashes. See string literal for details about string literals.

A back-reference is typically preceded by an additional backslash. For example, if you want to write a back-reference \& in replacement with a double-quoted string literal, you need to write "..\\&..".

If you want to write a non-back-reference string \& in replacement, you need first to escape the backslash to prevent this method from interpreting it as a back-reference, and then you need to escape the backslashes again to prevent a string literal from consuming them: "..\\\\&..".

You may want to use the block form to avoid a lot of backslashes.

Hash replacement

If argument replacement is a hash, and pattern matches one of its keys, the replacing string is the value for that key:

h = {'foo' => 'bar', 'baz' => 'bat'}
'food'.sub('foo', h) # => "bard"

Note that a symbol key does not match:

h = {foo: 'bar', baz: 'bat'}
'food'.sub('foo', h) # => "d"

Block

In the block form, the current match string is passed to the block; the block’s return value becomes the replacing string:

 s = '@'
'1234'.gsub(/\d/) {|match| s.succ! } # => "ABCD"

Special match variables such as $1, $2, $`, $&, and $' are set appropriately.

Whitespace in Strings

In class String, whitespace is defined as a contiguous sequence of characters consisting of any mixture of the following:

NL (null): "\x00", "\u0000".
HT (horizontal tab): "\x09", "\t".
LF (line feed): "\x0a", "\n".
VT (vertical tab): "\x0b", "\v".
FF (form feed): "\x0c", "\f".
CR (carriage return): "\x0d", "\r".
SP (space): "\x20", " ".

Whitespace is relevant for these methods:

lstrip, lstrip!: strip leading whitespace.
rstrip, rstrip!: strip trailing whitespace.
strip, strip!: strip leading and trailing whitespace.

`String` Slices

A slice of a string is a substring that is selected by certain criteria.

These instance methods make use of slicing:

String#[] (also aliased as String#slice) returns a slice copied from self.
String#[]= returns a copy of self with a slice replaced.
String#slice! returns self with a slice removed.

Each of the above methods takes arguments that determine the slice to be copied or replaced.

The arguments have several forms. For string string, the forms are:

string[index].
string[start, length].
string[range].
string[regexp, capture = 0].
string[substring].

string[index]

When non-negative integer argument index is given, the slice is the 1-character substring found in self at character offset index:

'bar'[0]       # => "b"
'bar'[2]       # => "r"
'bar'[20]      # => nil
'тест'[2]      # => "с"
'こんにちは'[4]  # => "は"

When negative integer index is given, the slice begins at the offset given by counting backward from the end of self:

'bar'[-3]         # => "b"
'bar'[-1]         # => "r"
'bar'[-20]        # => nil

string[start, length]

When non-negative integer arguments start and length are given, the slice begins at character offset start, if it exists, and continues for length characters, if available:

'foo'[0, 2]       # => "fo"
'тест'[1, 2]      # => "ес"
'こんにちは'[2, 2]  # => "にち"
# Zero length.
'foo'[2, 0]       # => ""
# Length not entirely available.
'foo'[1, 200]     # => "oo"
# Start out of range.
'foo'[4, 2]      # => nil

Special case: if start is equal to the length of self, the slice is a new empty string:

'foo'[3, 2]   # => ""
'foo'[3, 200] # => ""

When negative start and non-negative length are given, the slice beginning is determined by counting backward from the end of self, and the slice continues for length characters, if available:

'foo'[-2, 2]    # => "oo"
'foo'[-2, 200]  # => "oo"
# Start out of range.
'foo'[-4, 2]     # => nil

When negative length is given, there is no slice:

'foo'[1, -1]  # => nil
'foo'[-2, -1] # => nil

string[range]

When Range argument range is given, creates a substring of string using the indices in range. The slice is then determined as above:

'foo'[0..1]    # => "fo"
'foo'[0, 2]    # => "fo"

'foo'[2...2]   # => ""
'foo'[2, 0]    # => ""

'foo'[1..200]  # => "oo"
'foo'[1, 200]  # => "oo"

'foo'[4..5]    # => nil
'foo'[4, 2]    # => nil

'foo'[-4..-3]  # => nil
'foo'[-4, 2]   # => nil

'foo'[3..4]    # => ""
'foo'[3, 2]    # => ""

'foo'[-2..-1]  # => "oo"
'foo'[-2, 2]   # => "oo"

'foo'[-2..197] # => "oo"
'foo'[-2, 200] # => "oo"

string[regexp, capture = 0]

When the Regexp argument regexp is given, and the capture argument is 0, the slice is the first matching substring found in self:

'foo'[/o/] # => "o"
'foo'[/x/] # => nil
s = 'hello there'
s[/[aeiou](.)\1/] # => "ell"
s[/[aeiou](.)\1/, 0] # => "ell"

If argument capture is given and not 0, it should be either an capture group index (integer) or a capture group name (string or symbol); the slice is the specified capture (see Groups and Captures at Regexp):

s = 'hello there'
s[/[aeiou](.)\1/, 1] # => "l"
s[/(?<vowel>[aeiou])(?<non_vowel>[^aeiou])/, "non_vowel"] # => "l"
s[/(?<vowel>[aeiou])(?<non_vowel>[^aeiou])/, :vowel] # => "e"

If an invalid capture group index is given, there is no slice. If an invalid capture group name is given, IndexError is raised.

string[substring]

When the single String argument substring is given, returns the substring from self if found, otherwise nil:

'foo'['oo'] # => "oo"
'foo'['xx'] # => nil

What’s Here

First, what’s elsewhere. Class String:

Inherits from class Object.
Includes module Comparable.

Here, class String provides methods that are useful for:

Methods for Creating a `String`

::new: Returns a new string.
::try_convert: Returns a new string created from a given object.

Methods for a Frozen/Unfrozen `String`

+@: Returns a string that is not frozen: self, if not frozen; self.dup otherwise.
-@: Returns a string that is frozen: self, if already frozen; self.freeze otherwise.
freeze: Freezes self, if not already frozen; returns self.

Methods for Querying

Counts

length, size: Returns the count of characters (not bytes).
empty?: Returns true if self.length is zero; false otherwise.
bytesize: Returns the count of bytes.
count: Returns the count of substrings matching given strings.

Substrings

=~: Returns the index of the first substring that matches a given Regexp or other object; returns nil if no match is found.
index: Returns the index of the first occurrence of a given substring; returns nil if none found.
rindex: Returns the index of the last occurrence of a given substring; returns nil if none found.
include?: Returns true if the string contains a given substring; false otherwise.
match: Returns a MatchData object if the string matches a given Regexp; nil otherwise.
match?: Returns true if the string matches a given Regexp; false otherwise.
start_with?: Returns true if the string begins with any of the given substrings.
end_with?: Returns true if the string ends with any of the given substrings.

Encodings

encoding: Returns the Encoding object that represents the encoding of the string.
unicode_normalized?: Returns true if the string is in Unicode normalized form; false otherwise.
valid_encoding?: Returns true if the string contains only characters that are valid for its encoding.
ascii_only?: Returns true if the string has only ASCII characters; false otherwise.

Other

sum: Returns a basic checksum for the string: the sum of each byte.
hash: Returns the integer hash code.

Methods for Comparing

==, ===: Returns true if a given other string has the same content as self.
eql?: Returns true if the content is the same as the given other string.
<=>: Returns -1, 0, or 1 as a given other string is smaller than, equal to, or larger than self.
casecmp: Ignoring case, returns -1, 0, or 1 as a given other string is smaller than, equal to, or larger than self.
casecmp?: Returns true if the string is equal to a given string after Unicode case folding; false otherwise.

Methods for Modifying a `String`

Each of these methods modifies self.

Insertion

insert: Returns self with a given string inserted at a given offset.
<<: Returns self concatenated with a given string or integer.

Substitution

sub!: Replaces the first substring that matches a given pattern with a given replacement string; returns self if any changes, nil otherwise.
gsub!: Replaces each substring that matches a given pattern with a given replacement string; returns self if any changes, nil otherwise.
succ!, next!: Returns self modified to become its own successor.
replace: Returns self with its entire content replaced by a given string.
reverse!: Returns self with its characters in reverse order.
setbyte: Sets the byte at a given integer offset to a given value; returns the argument.
tr!: Replaces specified characters in self with specified replacement characters; returns self if any changes, nil otherwise.
tr_s!: Replaces specified characters in self with specified replacement characters, removing duplicates from the substrings that were modified; returns self if any changes, nil otherwise.

Casing

capitalize!: Upcases the initial character and downcases all others; returns self if any changes, nil otherwise.
downcase!: Downcases all characters; returns self if any changes, nil otherwise.
upcase!: Upcases all characters; returns self if any changes, nil otherwise.
swapcase!: Upcases each downcase character and downcases each upcase character; returns self if any changes, nil otherwise.

Encoding

encode!: Returns self with all characters transcoded from one given encoding into another.
unicode_normalize!: Unicode-normalizes self; returns self.
scrub!: Replaces each invalid byte with a given character; returns self.
force_encoding: Changes the encoding to a given encoding; returns self.

Deletion

clear: Removes all content, so that self is empty; returns self.
slice!, []=: Removes a substring determined by a given index, start/length, range, regexp, or substring.
squeeze!: Removes contiguous duplicate characters; returns self.
delete!: Removes characters as determined by the intersection of substring arguments.
lstrip!: Removes leading whitespace; returns self if any changes, nil otherwise.
rstrip!: Removes trailing whitespace; returns self if any changes, nil otherwise.
strip!: Removes leading and trailing whitespace; returns self if any changes, nil otherwise.
chomp!: Removes trailing record separator, if found; returns self if any changes, nil otherwise.
chop!: Removes trailing newline characters if found; otherwise removes the last character; returns self if any changes, nil otherwise.

Methods for Converting to New `String`

Each of these methods returns a new String based on self, often just a modified copy of self.

Extension

*: Returns the concatenation of multiple copies of self,
+: Returns the concatenation of self and a given other string.
center: Returns a copy of self centered between pad substring.
concat: Returns the concatenation of self with given other strings.
prepend: Returns the concatenation of a given other string with self.
ljust: Returns a copy of self of a given length, right-padded with a given other string.
rjust: Returns a copy of self of a given length, left-padded with a given other string.

Encoding

b: Returns a copy of self with ASCII-8BIT encoding.
scrub: Returns a copy of self with each invalid byte replaced with a given character.
unicode_normalize: Returns a copy of self with each character Unicode-normalized.
encode: Returns a copy of self with all characters transcoded from one given encoding into another.

Substitution

dump: Returns a copy of self with all non-printing characters replaced by xHH notation and all special characters escaped.
undump: Returns a copy of self with all \xNN notation replace by \uNNNN notation and all escaped characters unescaped.
sub: Returns a copy of self with the first substring matching a given pattern replaced with a given replacement string;.
gsub: Returns a copy of self with each substring that matches a given pattern replaced with a given replacement string.
succ, next: Returns the string that is the successor to self.
reverse: Returns a copy of self with its characters in reverse order.
tr: Returns a copy of self with specified characters replaced with specified replacement characters.
tr_s: Returns a copy of self with specified characters replaced with specified replacement characters, removing duplicates from the substrings that were modified.
%: Returns the string resulting from formatting a given object into self

Casing

capitalize: Returns a copy of self with the first character upcased and all other characters downcased.
downcase: Returns a copy of self with all characters downcased.
upcase: Returns a copy of self with all characters upcased.
swapcase: Returns a copy of self with all upcase characters downcased and all downcase characters upcased.

Deletion

delete: Returns a copy of self with characters removed
delete_prefix: Returns a copy of self with a given prefix removed.
delete_suffix: Returns a copy of self with a given suffix removed.
lstrip: Returns a copy of self with leading whitespace removed.
rstrip: Returns a copy of self with trailing whitespace removed.
strip: Returns a copy of self with leading and trailing whitespace removed.
chomp: Returns a copy of self with a trailing record separator removed, if found.
chop: Returns a copy of self with trailing newline characters or the last character removed.
squeeze: Returns a copy of self with contiguous duplicate characters removed.
[], slice: Returns a substring determined by a given index, start/length, or range, or string.
byteslice: Returns a substring determined by a given index, start/length, or range.
chr: Returns the first character.

Duplication

to_s, $to_str: If self is a subclass of String, returns self copied into a String; otherwise, returns self.

Methods for Converting to Non-`String`

Each of these methods converts the contents of self to a non-String.

Characters, Bytes, and Clusters

bytes: Returns an array of the bytes in self.
chars: Returns an array of the characters in self.
codepoints: Returns an array of the integer ordinals in self.
getbyte: Returns an integer byte as determined by a given index.
grapheme_clusters: Returns an array of the grapheme clusters in self.

Splitting

lines: Returns an array of the lines in self, as determined by a given record separator.
partition: Returns a 3-element array determined by the first substring that matches a given substring or regexp,
rpartition: Returns a 3-element array determined by the last substring that matches a given substring or regexp,
split: Returns an array of substrings determined by a given delimiter – regexp or string – or, if a block given, passes those substrings to the block.

Matching

scan: Returns an array of substrings matching a given regexp or string, or, if a block given, passes each matching substring to the block.
unpack: Returns an array of substrings extracted from self according to a given format.
unpack1: Returns the first substring extracted from self according to a given format.

Numerics

hex: Returns the integer value of the leading characters, interpreted as hexadecimal digits.
oct: Returns the integer value of the leading characters, interpreted as octal digits.
ord: Returns the integer ordinal of the first character in self.
to_i: Returns the integer value of leading characters, interpreted as an integer.
to_f: Returns the floating-point value of leading characters, interpreted as a floating-point number.

Strings and Symbols

inspect: Returns copy of self, enclosed in double-quotes, with special characters escaped.
to_sym, intern: Returns the symbol corresponding to self.

Methods for Iterating

each_byte: Calls the given block with each successive byte in self.
each_char: Calls the given block with each successive character in self.
each_codepoint: Calls the given block with each successive integer codepoint in self.
each_grapheme_cluster: Calls the given block with each successive grapheme cluster in self.
each_line: Calls the given block with each successive line in self, as determined by a given record separator.
upto: Calls the given block with each string value returned by successive calls to succ.

Class Methods

String.new(string = '', **opts) → new_string

string.c View on GitHub

          
            static VALUE
rb_str_init(int argc, VALUE *argv, VALUE str)
{
    static ID keyword_ids[2];
    VALUE orig, opt, venc, vcapa;
    VALUE kwargs[2];
    rb_encoding *enc = 0;
    int n;

    if (!keyword_ids[0]) {
        keyword_ids[0] = rb_id_encoding();
        CONST_ID(keyword_ids[1], "capacity");
    }

    n = rb_scan_args(argc, argv, "01:", &orig, &opt);
    if (!NIL_P(opt)) {
        rb_get_kwargs(opt, keyword_ids, 0, 2, kwargs);
        venc = kwargs[0];
        vcapa = kwargs[1];
        if (!UNDEF_P(venc) && !NIL_P(venc)) {
            enc = rb_to_encoding(venc);
        }
        if (!UNDEF_P(vcapa) && !NIL_P(vcapa)) {
            long capa = NUM2LONG(vcapa);
            long len = 0;
            int termlen = enc ? rb_enc_mbminlen(enc) : 1;

            if (capa < STR_BUF_MIN_SIZE) {
                capa = STR_BUF_MIN_SIZE;
            }
            if (n == 1) {
                StringValue(orig);
                len = RSTRING_LEN(orig);
                if (capa < len) {
                    capa = len;
                }
                if (orig == str) n = 0;
            }
            str_modifiable(str);
            if (STR_EMBED_P(str) || FL_TEST(str, STR_SHARED|STR_NOFREE)) {
                /* make noembed always */
                const size_t size = (size_t)capa + termlen;
                const char *const old_ptr = RSTRING_PTR(str);
                const size_t osize = RSTRING_LEN(str) + TERM_LEN(str);
                char *new_ptr = ALLOC_N(char, size);
                if (STR_EMBED_P(str)) RUBY_ASSERT((long)osize <= str_embed_capa(str));
                memcpy(new_ptr, old_ptr, osize < size ? osize : size);
                FL_UNSET_RAW(str, STR_SHARED|STR_NOFREE);
                RSTRING(str)->as.heap.ptr = new_ptr;
            }
            else if (STR_HEAP_SIZE(str) != (size_t)capa + termlen) {
                SIZED_REALLOC_N(RSTRING(str)->as.heap.ptr, char,
                        (size_t)capa + termlen, STR_HEAP_SIZE(str));
            }
            STR_SET_LEN(str, len);
            TERM_FILL(&RSTRING(str)->as.heap.ptr[len], termlen);
            if (n == 1) {
                memcpy(RSTRING(str)->as.heap.ptr, RSTRING_PTR(orig), len);
                rb_enc_cr_str_exact_copy(str, orig);
            }
            FL_SET(str, STR_NOEMBED);
            RSTRING(str)->as.heap.aux.capa = capa;
        }
        else if (n == 1) {
            rb_str_replace(str, orig);
        }
        if (enc) {
            rb_enc_associate(str, enc);
            ENC_CODERANGE_CLEAR(str);
        }
    }
    else if (n == 1) {
        rb_str_replace(str, orig);
    }
    return str;
}

Returns a new String that is a copy of string.

With no arguments, returns the empty string with the Encoding ASCII-8BIT:

s = String.new
s # => ""
s.encoding # => #<Encoding:ASCII-8BIT>

With optional argument string and no keyword arguments, returns a copy of string with the same encoding:

String.new('foo')               # => "foo"
String.new('тест')              # => "тест"
String.new('こんにちは')          # => "こんにちは"

(Unlike String.new, a string literal like '' or a string literal always has script encoding.)

With optional keyword argument encoding, returns a copy of string with the specified encoding; the encoding may be an Encoding object, an encoding name, or an encoding name alias:

String.new('foo', encoding: Encoding::US_ASCII).encoding # => #<Encoding:US-ASCII>
String.new('foo', encoding: 'US-ASCII').encoding         # => #<Encoding:US-ASCII>
String.new('foo', encoding: 'ASCII').encoding            # => #<Encoding:US-ASCII>

The given encoding need not be valid for the string’s content, and that validity is not checked:

s = String.new('こんにちは', encoding: 'ascii')
s.valid_encoding? # => false

But the given encoding itself is checked:

String.new('foo', encoding: 'bar') # Raises ArgumentError.

With optional keyword argument capacity, returns a copy of string (or an empty string, if string is not given); the given capacity is advisory only, and may or may not set the size of the internal buffer, which may in turn affect performance:

String.new(capacity: 1)
String.new('foo', capacity: 4096)

The string, encoding, and capacity arguments may all be used together:

String.new('hello', encoding: 'UTF-8', capacity: 25)

String.try_convert(object) → object, new_string, or nil

string.c View on GitHub

          
            static VALUE
rb_str_s_try_convert(VALUE dummy, VALUE str)
{
    return rb_check_string_type(str);
}

If object is a String object, returns object.

Otherwise if object responds to :to_str, calls object.to_str and returns the result.

Returns nil if object does not respond to :to_str.

Raises an exception unless object.to_str returns a String object.

Instance Methods

string % object → new_string

string.c View on GitHub

          
            static VALUE
rb_str_format_m(VALUE str, VALUE arg)
{
    VALUE tmp = rb_check_array_type(arg);

    if (!NIL_P(tmp)) {
        return rb_str_format(RARRAY_LENINT(tmp), RARRAY_CONST_PTR(tmp), str);
    }
    return rb_str_format(1, &arg, str);
}

Returns the result of formatting object into the format specification self (see Kernel#sprintf for formatting details):

"%05d" % 123 # => "00123"

If self contains multiple substitutions, object must be an Array or Hash containing the values to be substituted:

"%-5s: %016x" % [ "ID", self.object_id ] # => "ID   : 00002b054ec93168"
"foo = %{foo}" % {foo: 'bar'} # => "foo = bar"
"foo = %{foo}, baz = %{baz}" % {foo: 'bar', baz: 'bat'} # => "foo = bar, baz = bat"

string * integer → new_string

string.c View on GitHub

          
            VALUE
rb_str_times(VALUE str, VALUE times)
{
    VALUE str2;
    long n, len;
    char *ptr2;
    int termlen;

    if (times == INT2FIX(1)) {
        return str_duplicate(rb_cString, str);
    }
    if (times == INT2FIX(0)) {
        str2 = str_alloc_embed(rb_cString, 0);
        rb_enc_copy(str2, str);
        return str2;
    }
    len = NUM2LONG(times);
    if (len < 0) {
        rb_raise(rb_eArgError, "negative argument");
    }
    if (RSTRING_LEN(str) == 1 && RSTRING_PTR(str)[0] == 0) {
        if (STR_EMBEDDABLE_P(len, 1)) {
            str2 = str_alloc_embed(rb_cString, len + 1);
            memset(RSTRING_PTR(str2), 0, len + 1);
        }
        else {
            str2 = str_alloc_heap(rb_cString);
            RSTRING(str2)->as.heap.aux.capa = len;
            RSTRING(str2)->as.heap.ptr = ZALLOC_N(char, (size_t)len + 1);
        }
        STR_SET_LEN(str2, len);
        rb_enc_copy(str2, str);
        return str2;
    }
    if (len && LONG_MAX/len <  RSTRING_LEN(str)) {
        rb_raise(rb_eArgError, "argument too big");
    }

    len *= RSTRING_LEN(str);
    termlen = TERM_LEN(str);
    str2 = str_new0(rb_cString, 0, len, termlen);
    ptr2 = RSTRING_PTR(str2);
    if (len) {
        n = RSTRING_LEN(str);
        memcpy(ptr2, RSTRING_PTR(str), n);
        while (n <= len/2) {
            memcpy(ptr2 + n, ptr2, n);
            n *= 2;
        }
        memcpy(ptr2 + n, ptr2, len-n);
    }
    STR_SET_LEN(str2, len);
    TERM_FILL(&ptr2[len], termlen);
    rb_enc_cr_str_copy_for_substr(str2, str);

    return str2;
}

Returns a new String containing integer copies of self:

"Ho! " * 3 # => "Ho! Ho! Ho! "
"Ho! " * 0 # => ""

string + other_string → new_string

string.c View on GitHub

          
            VALUE
rb_str_plus(VALUE str1, VALUE str2)
{
    VALUE str3;
    rb_encoding *enc;
    char *ptr1, *ptr2, *ptr3;
    long len1, len2;
    int termlen;

    StringValue(str2);
    enc = rb_enc_check_str(str1, str2);
    RSTRING_GETMEM(str1, ptr1, len1);
    RSTRING_GETMEM(str2, ptr2, len2);
    termlen = rb_enc_mbminlen(enc);
    if (len1 > LONG_MAX - len2) {
        rb_raise(rb_eArgError, "string size too big");
    }
    str3 = str_new0(rb_cString, 0, len1+len2, termlen);
    ptr3 = RSTRING_PTR(str3);
    memcpy(ptr3, ptr1, len1);
    memcpy(ptr3+len1, ptr2, len2);
    TERM_FILL(&ptr3[len1+len2], termlen);

    ENCODING_CODERANGE_SET(str3, rb_enc_to_index(enc),
                           ENC_CODERANGE_AND(ENC_CODERANGE(str1), ENC_CODERANGE(str2)));
    RB_GC_GUARD(str1);
    RB_GC_GUARD(str2);
    return str3;
}

Returns a new String containing other_string concatenated to self:

"Hello from " + self.to_s # => "Hello from main"

+string → new_string or self

string.c View on GitHub

          
            static VALUE
str_uplus(VALUE str)
{
    if (OBJ_FROZEN(str)) {
        return rb_str_dup(str);
    }
    else {
        return str;
    }
}

Returns self if self is not frozen.

Otherwise returns self.dup, which is not frozen.

-string → frozen_string

string.c View on GitHub

          
            static VALUE
str_uminus(VALUE str)
{
    if (!BARE_STRING_P(str) && !rb_obj_frozen_p(str)) {
        str = rb_str_dup(str);
    }
    return rb_fstring(str);
}

Returns a frozen, possibly pre-existing copy of the string.

The returned String will be deduplicated as long as it does not have any instance variables set on it and is not a String subclass.

Note that -string variant is more convenient for defining constants:

FILENAME = -'config/database.yml'

while dedup is better suitable for using the method in chains of calculations:

@url_list.concat(urls.map(&:dedup))

string << object → string

string.c View on GitHub

          
            VALUE
rb_str_concat(VALUE str1, VALUE str2)
{
    unsigned int code;
    rb_encoding *enc = STR_ENC_GET(str1);
    int encidx;

    if (RB_INTEGER_TYPE_P(str2)) {
        if (rb_num_to_uint(str2, &code) == 0) {
        }
        else if (FIXNUM_P(str2)) {
            rb_raise(rb_eRangeError, "%ld out of char range", FIX2LONG(str2));
        }
        else {
            rb_raise(rb_eRangeError, "bignum out of char range");
        }
    }
    else {
        return rb_str_append(str1, str2);
    }

    encidx = rb_ascii8bit_appendable_encoding_index(enc, code);
    if (encidx >= 0) {
        char buf[1];
        buf[0] = (char)code;
        rb_str_cat(str1, buf, 1);
        if (encidx != rb_enc_to_index(enc)) {
            rb_enc_associate_index(str1, encidx);
            ENC_CODERANGE_SET(str1, ENC_CODERANGE_VALID);
        }
    }
    else {
        long pos = RSTRING_LEN(str1);
        int cr = ENC_CODERANGE(str1);
        int len;
        char *buf;

        switch (len = rb_enc_codelen(code, enc)) {
          case ONIGERR_INVALID_CODE_POINT_VALUE:
            rb_raise(rb_eRangeError, "invalid codepoint 0x%X in %s", code, rb_enc_name(enc));
            break;
          case ONIGERR_TOO_BIG_WIDE_CHAR_VALUE:
          case 0:
            rb_raise(rb_eRangeError, "%u out of char range", code);
            break;
        }
        buf = ALLOCA_N(char, len + 1);
        rb_enc_mbcput(code, buf, enc);
        if (rb_enc_precise_mbclen(buf, buf + len + 1, enc) != len) {
            rb_raise(rb_eRangeError, "invalid codepoint 0x%X in %s", code, rb_enc_name(enc));
        }
        rb_str_resize(str1, pos+len);
        memcpy(RSTRING_PTR(str1) + pos, buf, len);
        if (cr == ENC_CODERANGE_7BIT && code > 127) {
            cr = ENC_CODERANGE_VALID;
        }
        else if (cr == ENC_CODERANGE_BROKEN) {
            cr = ENC_CODERANGE_UNKNOWN;
        }
        ENC_CODERANGE_SET(str1, cr);
    }
    return str1;
}

Concatenates object to self and returns self:

s = 'foo'
s << 'bar' # => "foobar"
s          # => "foobar"

If object is an Integer, the value is considered a codepoint and converted to a character before concatenation:

s = 'foo'
s << 33 # => "foo!"

Related: String#concat, which takes multiple arguments.

string <=> other_string → -1, 0, 1, or nil

string.c View on GitHub

          
            static VALUE
rb_str_cmp_m(VALUE str1, VALUE str2)
{
    int result;
    VALUE s = rb_check_string_type(str2);
    if (NIL_P(s)) {
        return rb_invcmp(str1, str2);
    }
    result = rb_str_cmp(str1, s);
    return INT2FIX(result);
}

Compares self and other_string, returning:

-1 if other_string is larger.
0 if the two are equal.
1 if other_string is smaller.
nil if the two are incomparable.

Examples:

'foo' <=> 'foo' # => 0
'foo' <=> 'food' # => -1
'food' <=> 'foo' # => 1
'FOO' <=> 'foo' # => -1
'foo' <=> 'FOO' # => 1
'foo' <=> 1 # => nil

string == object → true or false

string.c View on GitHub

          
            VALUE
rb_str_equal(VALUE str1, VALUE str2)
{
    if (str1 == str2) return Qtrue;
    if (!RB_TYPE_P(str2, T_STRING)) {
        if (!rb_respond_to(str2, idTo_str)) {
            return Qfalse;
        }
        return rb_equal(str2, str1);
    }
    return rb_str_eql_internal(str1, str2);
}

Returns true if object has the same length and content; as self; false otherwise:

s = 'foo'
s == 'foo' # => true
s == 'food' # => false
s == 'FOO' # => false

Returns false if the two strings’ encodings are not compatible:

"\u{e4 f6 fc}".encode("ISO-8859-1") == ("\u{c4 d6 dc}") # => false

If object is not an instance of String but responds to to_str, then the two strings are compared using object.==.

string === object → true or false

string.c View on GitHub

An alias for ==

string =~ regexp → integer or nil

string =~ object → integer or nil

string.c View on GitHub

          
            static VALUE
rb_str_match(VALUE x, VALUE y)
{
    switch (OBJ_BUILTIN_TYPE(y)) {
      case T_STRING:
        rb_raise(rb_eTypeError, "type mismatch: String given");

      case T_REGEXP:
        return rb_reg_match(y, x);

      default:
        return rb_funcall(y, idEqTilde, 1, x);
    }
}

Returns the Integer index of the first substring that matches the given regexp, or nil if no match found:

'foo' =~ /f/ # => 0
'foo' =~ /o/ # => 1
'foo' =~ /x/ # => nil

Note: also updates Global Variables at Regexp.

If the given object is not a Regexp, returns the value returned by object =~ self.

Note that string =~ regexp is different from regexp =~ string (see Regexp#=~):

number= nil
"no. 9" =~ /(?<number>\d+)/
number # => nil (not assigned)
/(?<number>\d+)/ =~ "no. 9"
number #=> "9"

string[index] → new_string or nil

string[start, length] → new_string or nil

string[range] → new_string or nil

string[regexp, capture = 0] → new_string or nil

string[substring] → new_string or nil

string.c View on GitHub

          
            static VALUE
rb_str_aref_m(int argc, VALUE *argv, VALUE str)
{
    if (argc == 2) {
        if (RB_TYPE_P(argv[0], T_REGEXP)) {
            return rb_str_subpat(str, argv[0], argv[1]);
        }
        else {
            long beg = NUM2LONG(argv[0]);
            long len = NUM2LONG(argv[1]);
            return rb_str_substr(str, beg, len);
        }
    }
    rb_check_arity(argc, 1, 2);
    return rb_str_aref(str, argv[0]);
}

Returns the substring of self specified by the arguments. See examples at String Slices.

string[index] = new_string

string[start, length] = new_string

string[range] = new_string

string[regexp, capture = 0] = new_string

string[substring] = new_string

string.c View on GitHub

          
            static VALUE
rb_str_aset_m(int argc, VALUE *argv, VALUE str)
{
    if (argc == 3) {
        if (RB_TYPE_P(argv[0], T_REGEXP)) {
            rb_str_subpat_set(str, argv[0], argv[1], argv[2]);
        }
        else {
            rb_str_update(str, NUM2LONG(argv[0]), NUM2LONG(argv[1]), argv[2]);
        }
        return argv[2];
    }
    rb_check_arity(argc, 2, 3);
    return rb_str_aset(str, argv[0], argv[1]);
}

Replaces all, some, or none of the contents of self; returns new_string. See String Slices.

A few examples:

s = 'foo'
s[2] = 'rtune'     # => "rtune"
s                  # => "fortune"
s[1, 5] = 'init'   # => "init"
s                  # => "finite"
s[3..4] = 'al'     # => "al"
s                  # => "finale"
s[/e$/] = 'ly'     # => "ly"
s                  # => "finally"
s['lly'] = 'ncial' # => "ncial"
s                  # => "financial"

ascii_only? → true or false

string.c View on GitHub

          
            static VALUE
rb_str_is_ascii_only_p(VALUE str)
{
    int cr = rb_enc_str_coderange(str);

    return RBOOL(cr == ENC_CODERANGE_7BIT);
}

Returns true if self contains only ASCII characters, false otherwise:

'abc'.ascii_only?         # => true
"abc\u{6666}".ascii_only? # => false

b → string

string.c View on GitHub

          
            static VALUE
rb_str_b(VALUE str)
{
    VALUE str2;
    if (STR_EMBED_P(str)) {
        str2 = str_alloc_embed(rb_cString, RSTRING_LEN(str) + TERM_LEN(str));
    }
    else {
        str2 = str_alloc_heap(rb_cString);
    }
    str_replace_shared_without_enc(str2, str);

    if (rb_enc_asciicompat(STR_ENC_GET(str))) {
        // BINARY strings can never be broken; they're either 7-bit ASCII or VALID.
        // If we know the receiver's code range then we know the result's code range.
        int cr = ENC_CODERANGE(str);
        switch (cr) {
          case ENC_CODERANGE_7BIT:
            ENC_CODERANGE_SET(str2, ENC_CODERANGE_7BIT);
            break;
          case ENC_CODERANGE_BROKEN:
          case ENC_CODERANGE_VALID:
            ENC_CODERANGE_SET(str2, ENC_CODERANGE_VALID);
            break;
          default:
            ENC_CODERANGE_CLEAR(str2);
            break;
        }
    }

    return str2;
}

Returns a copy of self that has ASCII-8BIT encoding; the underlying bytes are not modified:

s = "\x99"
s.encoding   # => #<Encoding:UTF-8>
t = s.b      # => "\x99"
t.encoding   # => #<Encoding:ASCII-8BIT>

s = "\u4095" # => "䂕"
s.encoding   # => #<Encoding:UTF-8>
s.bytes      # => [228, 130, 149]
t = s.b      # => "\xE4\x82\x95"
t.encoding   # => #<Encoding:ASCII-8BIT>
t.bytes      # => [228, 130, 149]

byteindex(substring, offset = 0) → integer or nil

byteindex(regexp, offset = 0) → integer or nil

string.c View on GitHub

          
            static VALUE
rb_str_byteindex_m(int argc, VALUE *argv, VALUE str)
{
    VALUE sub;
    VALUE initpos;
    long pos;

    if (rb_scan_args(argc, argv, "11", &sub, &initpos) == 2) {
        long slen = RSTRING_LEN(str);
        pos = NUM2LONG(initpos);
        if (pos < 0 ? (pos += slen) < 0 : pos > slen) {
            if (RB_TYPE_P(sub, T_REGEXP)) {
                rb_backref_set(Qnil);
            }
            return Qnil;
        }
    }
    else {
        pos = 0;
    }

    str_ensure_byte_pos(str, pos);

    if (RB_TYPE_P(sub, T_REGEXP)) {
        if (rb_reg_search(sub, str, pos, 0) >= 0) {
            VALUE match = rb_backref_get();
            struct re_registers *regs = RMATCH_REGS(match);
            pos = BEG(0);
            return LONG2NUM(pos);
        }
    }
    else {
        StringValue(sub);
        pos = rb_str_byteindex(str, sub, pos);
        if (pos >= 0) return LONG2NUM(pos);
    }
    return Qnil;
}

Returns the Integer byte-based index of the first occurrence of the given substring, or nil if none found:

'foo'.byteindex('f') # => 0
'foo'.byteindex('o') # => 1
'foo'.byteindex('oo') # => 1
'foo'.byteindex('ooo') # => nil

Returns the Integer byte-based index of the first match for the given Regexp regexp, or nil if none found:

'foo'.byteindex(/f/) # => 0
'foo'.byteindex(/o/) # => 1
'foo'.byteindex(/oo/) # => 1
'foo'.byteindex(/ooo/) # => nil

Integer argument offset, if given, specifies the byte-based position in the string to begin the search:

'foo'.byteindex('o', 1) # => 1
'foo'.byteindex('o', 2) # => 2
'foo'.byteindex('o', 3) # => nil

If offset is negative, counts backward from the end of self:

'foo'.byteindex('o', -1) # => 2
'foo'.byteindex('o', -2) # => 1
'foo'.byteindex('o', -3) # => 1
'foo'.byteindex('o', -4) # => nil

If offset does not land on character (codepoint) boundary, IndexError is raised.

byterindex(substring, offset = self.bytesize) → integer or nil

byterindex(regexp, offset = self.bytesize) → integer or nil

string.c View on GitHub

          
            static VALUE
rb_str_byterindex_m(int argc, VALUE *argv, VALUE str)
{
    VALUE sub;
    VALUE initpos;
    long pos, len = RSTRING_LEN(str);

    if (rb_scan_args(argc, argv, "11", &sub, &initpos) == 2) {
        pos = NUM2LONG(initpos);
        if (pos < 0 && (pos += len) < 0) {
            if (RB_TYPE_P(sub, T_REGEXP)) {
                rb_backref_set(Qnil);
            }
            return Qnil;
        }
        if (pos > len) pos = len;
    }
    else {
        pos = len;
    }

    str_ensure_byte_pos(str, pos);

    if (RB_TYPE_P(sub, T_REGEXP)) {
        if (rb_reg_search(sub, str, pos, 1) >= 0) {
            VALUE match = rb_backref_get();
            struct re_registers *regs = RMATCH_REGS(match);
            pos = BEG(0);
            return LONG2NUM(pos);
        }
    }
    else {
        StringValue(sub);
        pos = rb_str_byterindex(str, sub, pos);
        if (pos >= 0) return LONG2NUM(pos);
    }
    return Qnil;
}

Returns the Integer byte-based index of the last occurrence of the given substring, or nil if none found:

'foo'.byterindex('f') # => 0
'foo'.byterindex('o') # => 2
'foo'.byterindex('oo') # => 1
'foo'.byterindex('ooo') # => nil

Returns the Integer byte-based index of the last match for the given Regexp regexp, or nil if none found:

'foo'.byterindex(/f/) # => 0
'foo'.byterindex(/o/) # => 2
'foo'.byterindex(/oo/) # => 1
'foo'.byterindex(/ooo/) # => nil

The last match means starting at the possible last position, not the last of longest matches.

'foo'.byterindex(/o+/) # => 2
$~ #=> #<MatchData "o">

To get the last longest match, needs to combine with negative lookbehind.

'foo'.byterindex(/(?<!o)o+/) # => 1
$~ #=> #<MatchData "oo">

Or String#byteindex with negative lookforward.

'foo'.byteindex(/o+(?!.*o)/) # => 1
$~ #=> #<MatchData "oo">

Integer argument offset, if given and non-negative, specifies the maximum starting byte-based position in the

string to _end_ the search:

 'foo'.byterindex('o', 0) # => nil
 'foo'.byterindex('o', 1) # => 1
 'foo'.byterindex('o', 2) # => 2
 'foo'.byterindex('o', 3) # => 2

If offset is a negative Integer, the maximum starting position in the string to end the search is the sum of the string’s length and offset:

'foo'.byterindex('o', -1) # => 2
'foo'.byterindex('o', -2) # => 1
'foo'.byterindex('o', -3) # => nil
'foo'.byterindex('o', -4) # => nil

If offset does not land on character (codepoint) boundary, IndexError is raised.

Related: String#byteindex.

bytes → array_of_bytes

string.c View on GitHub

          
            static VALUE
rb_str_bytes(VALUE str)
{
    VALUE ary = WANTARRAY("bytes", RSTRING_LEN(str));
    return rb_str_enumerate_bytes(str, ary);
}

Returns an array of the bytes in self:

'hello'.bytes # => [104, 101, 108, 108, 111]
'тест'.bytes  # => [209, 130, 208, 181, 209, 129, 209, 130]
'こんにちは'.bytes
# => [227, 129, 147, 227, 130, 147, 227, 129, 171, 227, 129, 161, 227, 129, 175]

bytesize → integer

string.c View on GitHub

          
            VALUE
rb_str_bytesize(VALUE str)
{
    return LONG2NUM(RSTRING_LEN(str));
}

Returns the count of bytes (not characters) in self:

'foo'.bytesize        # => 3
'тест'.bytesize       # => 8
'こんにちは'.bytesize   # => 15

Contrast with String#length:

'foo'.length       # => 3
'тест'.length      # => 4
'こんにちは'.length  # => 5

byteslice(index, length = 1) → string or nil

byteslice(range) → string or nil

string.c View on GitHub

          
            static VALUE
rb_str_byteslice(int argc, VALUE *argv, VALUE str)
{
    if (argc == 2) {
        long beg = NUM2LONG(argv[0]);
        long len = NUM2LONG(argv[1]);
        return str_byte_substr(str, beg, len, TRUE);
    }
    rb_check_arity(argc, 1, 2);
    return str_byte_aref(str, argv[0]);
}

Returns a substring of self, or nil if the substring cannot be constructed.

With integer arguments index and length given, returns the substring beginning at the given index of the given length (if possible), or nil if length is negative or index falls outside of self:

s = '0123456789' # => "0123456789"
s.byteslice(2)   # => "2"
s.byteslice(200) # => nil
s.byteslice(4, 3)  # => "456"
s.byteslice(4, 30) # => "456789"
s.byteslice(4, -1) # => nil
s.byteslice(40, 2) # => nil

In either case above, counts backwards from the end of self if index is negative:

s = '0123456789'   # => "0123456789"
s.byteslice(-4)    # => "6"
s.byteslice(-4, 3) # => "678"

With Range argument range given, returns byteslice(range.begin, range.size):

s = '0123456789'    # => "0123456789"
s.byteslice(4..6)   # => "456"
s.byteslice(-6..-4) # => "456"
s.byteslice(5..2)   # => "" # range.size is zero.
s.byteslice(40..42) # => nil

In all cases, a returned string has the same encoding as self:

s.encoding              # => #<Encoding:UTF-8>
s.byteslice(4).encoding # => #<Encoding:UTF-8>

bytesplice(index, length, str) → string

bytesplice(index, length, str, str_index, str_length) → string

bytesplice(range, str) → string

bytesplice(range, str, str_range) → string

string.c View on GitHub

          
            static VALUE
rb_str_bytesplice(int argc, VALUE *argv, VALUE str)
{
    long beg, len, vbeg, vlen;
    VALUE val;
    rb_encoding *enc;
    int cr;

    rb_check_arity(argc, 2, 5);
    if (!(argc == 2 || argc == 3 || argc == 5)) {
        rb_raise(rb_eArgError, "wrong number of arguments (given %d, expected 2, 3, or 5)", argc);
    }
    if (argc == 2 || (argc == 3 && !RB_INTEGER_TYPE_P(argv[0]))) {
        if (!rb_range_beg_len(argv[0], &beg, &len, RSTRING_LEN(str), 2)) {
            rb_raise(rb_eTypeError, "wrong argument type %s (expected Range)",
                     rb_builtin_class_name(argv[0]));
        }
        val = argv[1];
        StringValue(val);
        if (argc == 2) {
            /* bytesplice(range, str) */
            vbeg = 0;
            vlen = RSTRING_LEN(val);
        }
        else {
            /* bytesplice(range, str, str_range) */
            if (!rb_range_beg_len(argv[2], &vbeg, &vlen, RSTRING_LEN(val), 2)) {
                rb_raise(rb_eTypeError, "wrong argument type %s (expected Range)",
                         rb_builtin_class_name(argv[2]));
            }
        }
    }
    else {
        beg = NUM2LONG(argv[0]);
        len = NUM2LONG(argv[1]);
        val = argv[2];
        StringValue(val);
        if (argc == 3) {
            /* bytesplice(index, length, str) */
            vbeg = 0;
            vlen = RSTRING_LEN(val);
        }
        else {
            /* bytesplice(index, length, str, str_index, str_length) */
            vbeg = NUM2LONG(argv[3]);
            vlen = NUM2LONG(argv[4]);
        }
    }
    str_check_beg_len(str, &beg, &len);
    str_check_beg_len(val, &vbeg, &vlen);
    enc = rb_enc_check(str, val);
    str_modify_keep_cr(str);
    rb_str_update_1(str, beg, len, val, vbeg, vlen);
    rb_enc_associate(str, enc);
    cr = ENC_CODERANGE_AND(ENC_CODERANGE(str), ENC_CODERANGE(val));
    if (cr != ENC_CODERANGE_BROKEN)
        ENC_CODERANGE_SET(str, cr);
    return str;
}

Replaces some or all of the content of self with str, and returns self. The portion of the string affected is determined using the same criteria as String#byteslice, except that length cannot be omitted. If the replacement string is not the same length as the text it is replacing, the string will be adjusted accordingly.

If str_index and str_length, or str_range are given, the content of self is replaced by str.byteslice(str_index, str_length) or str.byteslice(str_range); however the substring of str is not allocated as a new string.

The form that take an Integer will raise an IndexError if the value is out of range; the Range form will raise a RangeError. If the beginning or ending offset does not land on character (codepoint) boundary, an IndexError will be raised.

capitalize(*options) → string

string.c View on GitHub

          
            static VALUE
rb_str_capitalize(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_UPCASE | ONIGENC_CASE_TITLECASE;
    VALUE ret;

    flags = check_case_options(argc, argv, flags);
    enc = str_true_enc(str);
    if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return str;
    if (flags&ONIGENC_CASE_ASCII_ONLY) {
        ret = rb_str_new(0, RSTRING_LEN(str));
        rb_str_ascii_casemap(str, ret, &flags, enc);
    }
    else {
        ret = rb_str_casemap(str, &flags, enc);
    }
    return ret;
}

Returns a string containing the characters in self; the first character is upcased; the remaining characters are downcased:

s = 'hello World!' # => "hello World!"
s.capitalize       # => "Hello world!"

The casing may be affected by the given options; see Case Mapping.

Related: String#capitalize!.

capitalize!(*options) → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_capitalize_bang(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_UPCASE | ONIGENC_CASE_TITLECASE;

    flags = check_case_options(argc, argv, flags);
    str_modify_keep_cr(str);
    enc = str_true_enc(str);
    if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return Qnil;
    if (flags&ONIGENC_CASE_ASCII_ONLY)
        rb_str_ascii_casemap(str, str, &flags, enc);
    else
        str_shared_replace(str, rb_str_casemap(str, &flags, enc));

    if (ONIGENC_CASE_MODIFIED&flags) return str;
    return Qnil;
}

Upcases the first character in self; downcases the remaining characters; returns self if any changes were made, nil otherwise:

s = 'hello World!' # => "hello World!"
s.capitalize!      # => "Hello world!"
s                  # => "Hello world!"
s.capitalize!      # => nil

The casing may be affected by the given options; see Case Mapping.

Related: String#capitalize.

casecmp(other_string) → -1, 0, 1, or nil

string.c View on GitHub

          
            static VALUE
rb_str_casecmp(VALUE str1, VALUE str2)
{
    VALUE s = rb_check_string_type(str2);
    if (NIL_P(s)) {
        return Qnil;
    }
    return str_casecmp(str1, s);
}

Compares self.downcase and other_string.downcase; returns:

-1 if other_string.downcase is larger.
0 if the two are equal.
1 if other_string.downcase is smaller.
nil if the two are incomparable.

Examples:

'foo'.casecmp('foo') # => 0
'foo'.casecmp('food') # => -1
'food'.casecmp('foo') # => 1
'FOO'.casecmp('foo') # => 0
'foo'.casecmp('FOO') # => 0
'foo'.casecmp(1) # => nil

See Case Mapping.

Related: String#casecmp?.

casecmp?(other_string) → true, false, or nil

string.c View on GitHub

          
            static VALUE
rb_str_casecmp_p(VALUE str1, VALUE str2)
{
    VALUE s = rb_check_string_type(str2);
    if (NIL_P(s)) {
        return Qnil;
    }
    return str_casecmp_p(str1, s);
}

Returns true if self and other_string are equal after Unicode case folding, otherwise false:

'foo'.casecmp?('foo') # => true
'foo'.casecmp?('food') # => false
'food'.casecmp?('foo') # => false
'FOO'.casecmp?('foo') # => true
'foo'.casecmp?('FOO') # => true

Returns nil if the two values are incomparable:

'foo'.casecmp?(1) # => nil

See Case Mapping.

Related: String#casecmp.

center(size, pad_string = ' ') → new_string

string.c View on GitHub

          
            static VALUE
rb_str_center(int argc, VALUE *argv, VALUE str)
{
    return rb_str_justify(argc, argv, str, 'c');
}

Returns a centered copy of self.

If integer argument size is greater than the size (in characters) of self, returns a new string of length size that is a copy of self, centered and padded on both ends with pad_string:

'hello'.center(10)       # => "  hello   "
'  hello'.center(10)     # => "   hello  "
'hello'.center(10, 'ab') # => "abhelloaba"
'тест'.center(10)        # => "   тест   "
'こんにちは'.center(10)    # => "  こんにちは   "

If size is not greater than the size of self, returns a copy of self:

'hello'.center(5)  # => "hello"
'hello'.center(1)  # => "hello"

chars → array_of_characters

string.c View on GitHub

          
            static VALUE
rb_str_chars(VALUE str)
{
    VALUE ary = WANTARRAY("chars", rb_str_strlen(str));
    return rb_str_enumerate_chars(str, ary);
}

Returns an array of the characters in self:

'hello'.chars     # => ["h", "e", "l", "l", "o"]
'тест'.chars      # => ["т", "е", "с", "т"]
'こんにちは'.chars # => ["こ", "ん", "に", "ち", "は"]

chomp(line_sep = $/) → new_string

string.c View on GitHub

          
            static VALUE
rb_str_chomp(int argc, VALUE *argv, VALUE str)
{
    VALUE rs = chomp_rs(argc, argv);
    if (NIL_P(rs)) return str_duplicate(rb_cString, str);
    return rb_str_subseq(str, 0, chompped_length(str, rs));
}

Returns a new string copied from self, with trailing characters possibly removed:

When line_sep is "\n", removes the last one or two characters if they are "\r", "\n", or "\r\n" (but not "\n\r"):

$/                    # => "\n"
"abc\r".chomp         # => "abc"
"abc\n".chomp         # => "abc"
"abc\r\n".chomp       # => "abc"
"abc\n\r".chomp       # => "abc\n"
"тест\r\n".chomp      # => "тест"
"こんにちは\r\n".chomp  # => "こんにちは"

When line_sep is '' (an empty string), removes multiple trailing occurrences of "\n" or "\r\n" (but not "\r" or "\n\r"):

"abc\n\n\n".chomp('')           # => "abc"
"abc\r\n\r\n\r\n".chomp('')     # => "abc"
"abc\n\n\r\n\r\n\n\n".chomp('') # => "abc"
"abc\n\r\n\r\n\r".chomp('')     # => "abc\n\r\n\r\n\r"
"abc\r\r\r".chomp('')           # => "abc\r\r\r"

When line_sep is neither "\n" nor '', removes a single trailing line separator if there is one:

'abcd'.chomp('d')  # => "abc"
'abcdd'.chomp('d') # => "abcd"

chomp!(line_sep = $/) → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_chomp_bang(int argc, VALUE *argv, VALUE str)
{
    VALUE rs;
    str_modifiable(str);
    if (RSTRING_LEN(str) == 0 && argc < 2) return Qnil;
    rs = chomp_rs(argc, argv);
    if (NIL_P(rs)) return Qnil;
    return rb_str_chomp_string(str, rs);
}

Like String#chomp, but modifies self in place; returns nil if no modification made, self otherwise.

chop → new_string

string.c View on GitHub

          
            static VALUE
rb_str_chop(VALUE str)
{
    return rb_str_subseq(str, 0, chopped_length(str));
}

Returns a new string copied from self, with trailing characters possibly removed.

Removes "\r\n" if those are the last two characters.

"abc\r\n".chop      # => "abc"
"тест\r\n".chop     # => "тест"
"こんにちは\r\n".chop # => "こんにちは"

Otherwise removes the last character if it exists.

'abcd'.chop     # => "abc"
'тест'.chop     # => "тес"
'こんにちは'.chop # => "こんにち"
''.chop         # => ""

If you only need to remove the newline separator at the end of the string, String#chomp is a better alternative.

chop! → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_chop_bang(VALUE str)
{
    str_modify_keep_cr(str);
    if (RSTRING_LEN(str) > 0) {
        long len;
        len = chopped_length(str);
        STR_SET_LEN(str, len);
        TERM_FILL(&RSTRING_PTR(str)[len], TERM_LEN(str));
        if (ENC_CODERANGE(str) != ENC_CODERANGE_7BIT) {
            ENC_CODERANGE_CLEAR(str);
        }
        return str;
    }
    return Qnil;
}

Like String#chop, but modifies self in place; returns nil if self is empty, self otherwise.

Related: String#chomp!.

chr → string

string.c View on GitHub

          
            static VALUE
rb_str_chr(VALUE str)
{
    return rb_str_substr(str, 0, 1);
}

Returns a string containing the first character of self:

s = 'foo' # => "foo"
s.chr     # => "f"

clear → self

string.c View on GitHub

          
            static VALUE
rb_str_clear(VALUE str)
{
    str_discard(str);
    STR_SET_EMBED(str);
    STR_SET_LEN(str, 0);
    RSTRING_PTR(str)[0] = 0;
    if (rb_enc_asciicompat(STR_ENC_GET(str)))
        ENC_CODERANGE_SET(str, ENC_CODERANGE_7BIT);
    else
        ENC_CODERANGE_SET(str, ENC_CODERANGE_VALID);
    return str;
}

Removes the contents of self:

s = 'foo' # => "foo"
s.clear   # => ""

codepoints → array_of_integers

string.c View on GitHub

          
            static VALUE
rb_str_codepoints(VALUE str)
{
    VALUE ary = WANTARRAY("codepoints", rb_str_strlen(str));
    return rb_str_enumerate_codepoints(str, ary);
}

Returns an array of the codepoints in self; each codepoint is the integer value for a character:

'hello'.codepoints     # => [104, 101, 108, 108, 111]
'тест'.codepoints      # => [1090, 1077, 1089, 1090]
'こんにちは'.codepoints # => [12371, 12435, 12395, 12385, 12399]

concat(*objects) → string

string.c View on GitHub

          
            static VALUE
rb_str_concat_multi(int argc, VALUE *argv, VALUE str)
{
    str_modifiable(str);

    if (argc == 1) {
        return rb_str_concat(str, argv[0]);
    }
    else if (argc > 1) {
        int i;
        VALUE arg_str = rb_str_tmp_new(0);
        rb_enc_copy(arg_str, str);
        for (i = 0; i < argc; i++) {
            rb_str_concat(arg_str, argv[i]);
        }
        rb_str_buf_append(str, arg_str);
    }

    return str;
}

Concatenates each object in objects to self and returns self:

s = 'foo'
s.concat('bar', 'baz') # => "foobarbaz"
s                      # => "foobarbaz"

For each given object object that is an Integer, the value is considered a codepoint and converted to a character before concatenation:

s = 'foo'
s.concat(32, 'bar', 32, 'baz') # => "foo bar baz"

Related: String#<<, which takes a single argument.

count(*selectors) → integer

string.c View on GitHub

          
            static VALUE
rb_str_count(int argc, VALUE *argv, VALUE str)
{
    char table[TR_TABLE_SIZE];
    rb_encoding *enc = 0;
    VALUE del = 0, nodel = 0, tstr;
    char *s, *send;
    int i;
    int ascompat;
    size_t n = 0;

    rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);

    tstr = argv[0];
    StringValue(tstr);
    enc = rb_enc_check(str, tstr);
    if (argc == 1) {
        const char *ptstr;
        if (RSTRING_LEN(tstr) == 1 && rb_enc_asciicompat(enc) &&
            (ptstr = RSTRING_PTR(tstr),
             ONIGENC_IS_ALLOWED_REVERSE_MATCH(enc, (const unsigned char *)ptstr, (const unsigned char *)ptstr+1)) &&
            !is_broken_string(str)) {
            int clen;
            unsigned char c = rb_enc_codepoint_len(ptstr, ptstr+1, &clen, enc);

            s = RSTRING_PTR(str);
            if (!s || RSTRING_LEN(str) == 0) return INT2FIX(0);
            send = RSTRING_END(str);
            while (s < send) {
                if (*(unsigned char*)s++ == c) n++;
            }
            return SIZET2NUM(n);
        }
    }

    tr_setup_table(tstr, table, TRUE, &del, &nodel, enc);
    for (i=1; i<argc; i++) {
        tstr = argv[i];
        StringValue(tstr);
        enc = rb_enc_check(str, tstr);
        tr_setup_table(tstr, table, FALSE, &del, &nodel, enc);
    }

    s = RSTRING_PTR(str);
    if (!s || RSTRING_LEN(str) == 0) return INT2FIX(0);
    send = RSTRING_END(str);
    ascompat = rb_enc_asciicompat(enc);
    while (s < send) {
        unsigned int c;

        if (ascompat && (c = *(unsigned char*)s) < 0x80) {
            if (table[c]) {
                n++;
            }
            s++;
        }
        else {
            int clen;
            c = rb_enc_codepoint_len(s, send, &clen, enc);
            if (tr_find(c, table, del, nodel)) {
                n++;
            }
            s += clen;
        }
    }

    return SIZET2NUM(n);
}

Returns the total number of characters in self that are specified by the given selectors (see Multiple Character Selectors):

a = "hello world"
a.count "lo"                   #=> 5
a.count "lo", "o"              #=> 2
a.count "hello", "^l"          #=> 4
a.count "ej-m"                 #=> 4

"hello^world".count "\\^aeiou" #=> 4
"hello-world".count "a\\-eo"   #=> 4

c = "hello world\\r\\n"
c.count "\\"                   #=> 2
c.count "\\A"                  #=> 0
c.count "X-\\w"                #=> 3

crypt(salt_str) → new_string

string.c View on GitHub

          
            static VALUE
rb_str_crypt(VALUE str, VALUE salt)
{
#ifdef HAVE_CRYPT_R
    VALUE databuf;
    struct crypt_data *data;
#   define CRYPT_END() ALLOCV_END(databuf)
#else
    extern char *crypt(const char *, const char *);
#   define CRYPT_END() rb_nativethread_lock_unlock(&crypt_mutex.lock)
#endif
    VALUE result;
    const char *s, *saltp;
    char *res;
#ifdef BROKEN_CRYPT
    char salt_8bit_clean[3];
#endif

    StringValue(salt);
    mustnot_wchar(str);
    mustnot_wchar(salt);
    s = StringValueCStr(str);
    saltp = RSTRING_PTR(salt);
    if (RSTRING_LEN(salt) < 2 || !saltp[0] || !saltp[1]) {
        rb_raise(rb_eArgError, "salt too short (need >=2 bytes)");
    }

#ifdef BROKEN_CRYPT
    if (!ISASCII((unsigned char)saltp[0]) || !ISASCII((unsigned char)saltp[1])) {
        salt_8bit_clean[0] = saltp[0] & 0x7f;
        salt_8bit_clean[1] = saltp[1] & 0x7f;
        salt_8bit_clean[2] = '\0';
        saltp = salt_8bit_clean;
    }
#endif
#ifdef HAVE_CRYPT_R
    data = ALLOCV(databuf, sizeof(struct crypt_data));
# ifdef HAVE_STRUCT_CRYPT_DATA_INITIALIZED
    data->initialized = 0;
# endif
    res = crypt_r(s, saltp, data);
#else
    crypt_mutex_initialize();
    rb_nativethread_lock_lock(&crypt_mutex.lock);
    res = crypt(s, saltp);
#endif
    if (!res) {
        int err = errno;
        CRYPT_END();
        rb_syserr_fail(err, "crypt");
    }
    result = rb_str_new_cstr(res);
    CRYPT_END();
    return result;
}

Returns the string generated by calling crypt(3) standard library function with str and salt_str, in this order, as its arguments. Please do not use this method any longer. It is legacy; provided only for backward compatibility with ruby scripts in earlier days. It is bad to use in contemporary programs for several reasons:

Behaviour of C’s crypt(3) depends on the OS it is run. The generated string lacks data portability.
On some OSes such as Mac OS, crypt(3) never fails (i.e. silently ends up in unexpected results).
On some OSes such as Mac OS, crypt(3) is not thread safe.
So-called “traditional” usage of crypt(3) is very very very weak. According to its manpage, Linux’s traditional crypt(3) output has only 2**56 variations; too easy to brute force today. And this is the default behaviour.
In order to make things robust some OSes implement so-called “modular” usage. To go through, you have to do a complex build-up of the salt_str parameter, by hand. Failure in generation of a proper salt string tends not to yield any errors; typos in parameters are normally not detectable.
- For instance, in the following example, the second invocation of String#crypt is wrong; it has a typo in “round=” (lacks “s”). However the call does not fail and something unexpected is generated.
```
"foo".crypt("$5$rounds=1000$salt$") # OK, proper usage
"foo".crypt("$5$round=1000$salt$")  # Typo not detected
```
Even in the “modular” mode, some hash functions are considered archaic and no longer recommended at all; for instance module $1$ is officially abandoned by its author: see phk.freebsd.dk/sagas/md5crypt_eol/ . For another instance module $3$ is considered completely broken: see the manpage of FreeBSD.
On some OS such as Mac OS, there is no modular mode. Yet, as written above, crypt(3) on Mac OS never fails. This means even if you build up a proper salt string it generates a traditional DES hash anyways, and there is no way for you to be aware of.
```
"foo".crypt("$5$rounds=1000$salt$") # => "$5fNPQMxC5j6."
```

If for some reason you cannot migrate to other secure contemporary password hashing algorithms, install the string-crypt gem and require 'string/crypt' to continue using it.

-string → frozen_string

dedup → frozen_string

string.c View on GitHub

An alias for -@

delete(*selectors) → new_string

string.c View on GitHub

          
            static VALUE
rb_str_delete(int argc, VALUE *argv, VALUE str)
{
    str = str_duplicate(rb_cString, str);
    rb_str_delete_bang(argc, argv, str);
    return str;
}

Returns a copy of self with characters specified by selectors removed (see Multiple Character Selectors):

"hello".delete "l","lo"        #=> "heo"
"hello".delete "lo"            #=> "he"
"hello".delete "aeiou", "^e"   #=> "hell"
"hello".delete "ej-m"          #=> "ho"

delete!(*selectors) → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_delete_bang(int argc, VALUE *argv, VALUE str)
{
    char squeez[TR_TABLE_SIZE];
    rb_encoding *enc = 0;
    char *s, *send, *t;
    VALUE del = 0, nodel = 0;
    int modify = 0;
    int i, ascompat, cr;

    if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return Qnil;
    rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
    for (i=0; i<argc; i++) {
        VALUE s = argv[i];

        StringValue(s);
        enc = rb_enc_check(str, s);
        tr_setup_table(s, squeez, i==0, &del, &nodel, enc);
    }

    str_modify_keep_cr(str);
    ascompat = rb_enc_asciicompat(enc);
    s = t = RSTRING_PTR(str);
    send = RSTRING_END(str);
    cr = ascompat ? ENC_CODERANGE_7BIT : ENC_CODERANGE_VALID;
    while (s < send) {
        unsigned int c;
        int clen;

        if (ascompat && (c = *(unsigned char*)s) < 0x80) {
            if (squeez[c]) {
                modify = 1;
            }
            else {
                if (t != s) *t = c;
                t++;
            }
            s++;
        }
        else {
            c = rb_enc_codepoint_len(s, send, &clen, enc);

            if (tr_find(c, squeez, del, nodel)) {
                modify = 1;
            }
            else {
                if (t != s) rb_enc_mbcput(c, t, enc);
                t += clen;
                if (cr == ENC_CODERANGE_7BIT) cr = ENC_CODERANGE_VALID;
            }
            s += clen;
        }
    }
    TERM_FILL(t, TERM_LEN(str));
    STR_SET_LEN(str, t - RSTRING_PTR(str));
    ENC_CODERANGE_SET(str, cr);

    if (modify) return str;
    return Qnil;
}

Like String#delete, but modifies self in place. Returns self if any changes were made, nil otherwise.

delete_prefix(prefix) → new_string

string.c View on GitHub

          
            static VALUE
rb_str_delete_prefix(VALUE str, VALUE prefix)
{
    long prefixlen;

    prefixlen = deleted_prefix_length(str, prefix);
    if (prefixlen <= 0) return str_duplicate(rb_cString, str);

    return rb_str_subseq(str, prefixlen, RSTRING_LEN(str) - prefixlen);
}

Returns a copy of self with leading substring prefix removed:

'hello'.delete_prefix('hel')      # => "lo"
'hello'.delete_prefix('llo')      # => "hello"
'тест'.delete_prefix('те')        # => "ст"
'こんにちは'.delete_prefix('こん')  # => "にちは"

delete_prefix!(prefix) → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_delete_prefix_bang(VALUE str, VALUE prefix)
{
    long prefixlen;
    str_modify_keep_cr(str);

    prefixlen = deleted_prefix_length(str, prefix);
    if (prefixlen <= 0) return Qnil;

    return rb_str_drop_bytes(str, prefixlen);
}

Like String#delete_prefix, except that self is modified in place. Returns self if the prefix is removed, nil otherwise.

delete_suffix(suffix) → new_string

string.c View on GitHub

          
            static VALUE
rb_str_delete_suffix(VALUE str, VALUE suffix)
{
    long suffixlen;

    suffixlen = deleted_suffix_length(str, suffix);
    if (suffixlen <= 0) return str_duplicate(rb_cString, str);

    return rb_str_subseq(str, 0, RSTRING_LEN(str) - suffixlen);
}

Returns a copy of self with trailing substring suffix removed:

'hello'.delete_suffix('llo')      # => "he"
'hello'.delete_suffix('hel')      # => "hello"
'тест'.delete_suffix('ст')        # => "те"
'こんにちは'.delete_suffix('ちは')  # => "こんに"

delete_suffix!(suffix) → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_delete_suffix_bang(VALUE str, VALUE suffix)
{
    long olen, suffixlen, len;
    str_modifiable(str);

    suffixlen = deleted_suffix_length(str, suffix);
    if (suffixlen <= 0) return Qnil;

    olen = RSTRING_LEN(str);
    str_modify_keep_cr(str);
    len = olen - suffixlen;
    STR_SET_LEN(str, len);
    TERM_FILL(&RSTRING_PTR(str)[len], TERM_LEN(str));
    if (ENC_CODERANGE(str) != ENC_CODERANGE_7BIT) {
        ENC_CODERANGE_CLEAR(str);
    }
    return str;
}

Like String#delete_suffix, except that self is modified in place. Returns self if the suffix is removed, nil otherwise.

downcase(*options) → string

string.c View on GitHub

          
            static VALUE
rb_str_downcase(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_DOWNCASE;
    VALUE ret;

    flags = check_case_options(argc, argv, flags);
    enc = str_true_enc(str);
    if (case_option_single_p(flags, enc, str)) {
        ret = rb_str_new(RSTRING_PTR(str), RSTRING_LEN(str));
        str_enc_copy_direct(ret, str);
        downcase_single(ret);
    }
    else if (flags&ONIGENC_CASE_ASCII_ONLY) {
        ret = rb_str_new(0, RSTRING_LEN(str));
        rb_str_ascii_casemap(str, ret, &flags, enc);
    }
    else {
        ret = rb_str_casemap(str, &flags, enc);
    }

    return ret;
}

Returns a string containing the downcased characters in self:

s = 'Hello World!' # => "Hello World!"
s.downcase         # => "hello world!"

The casing may be affected by the given options; see Case Mapping.

downcase!(*options) → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_downcase_bang(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_DOWNCASE;

    flags = check_case_options(argc, argv, flags);
    str_modify_keep_cr(str);
    enc = str_true_enc(str);
    if (case_option_single_p(flags, enc, str)) {
        if (downcase_single(str))
            flags |= ONIGENC_CASE_MODIFIED;
    }
    else if (flags&ONIGENC_CASE_ASCII_ONLY)
        rb_str_ascii_casemap(str, str, &flags, enc);
    else
        str_shared_replace(str, rb_str_casemap(str, &flags, enc));

    if (ONIGENC_CASE_MODIFIED&flags) return str;
    return Qnil;
}

Downcases the characters in self; returns self if any changes were made, nil otherwise:

s = 'Hello World!' # => "Hello World!"
s.downcase!        # => "hello world!"
s                  # => "hello world!"
s.downcase!        # => nil

The casing may be affected by the given options; see Case Mapping.

dump → string

string.c View on GitHub

          
            VALUE
rb_str_dump(VALUE str)
{
    int encidx = rb_enc_get_index(str);
    rb_encoding *enc = rb_enc_from_index(encidx);
    long len;
    const char *p, *pend;
    char *q, *qend;
    VALUE result;
    int u8 = (encidx == rb_utf8_encindex());
    static const char nonascii_suffix[] = ".dup.force_encoding(\"%s\")";

    len = 2;                    /* "" */
    if (!rb_enc_asciicompat(enc)) {
        len += strlen(nonascii_suffix) - rb_strlen_lit("%s");
        len += strlen(enc->name);
    }

    p = RSTRING_PTR(str); pend = p + RSTRING_LEN(str);
    while (p < pend) {
        int clen;
        unsigned char c = *p++;

        switch (c) {
          case '"':  case '\\':
          case '\n': case '\r':
          case '\t': case '\f':
          case '\013': case '\010': case '\007': case '\033':
            clen = 2;
            break;

          case '#':
            clen = IS_EVSTR(p, pend) ? 2 : 1;
            break;

          default:
            if (ISPRINT(c)) {
                clen = 1;
            }
            else {
                if (u8 && c > 0x7F) {   /* \u notation */
                    int n = rb_enc_precise_mbclen(p-1, pend, enc);
                    if (MBCLEN_CHARFOUND_P(n)) {
                        unsigned int cc = rb_enc_mbc_to_codepoint(p-1, pend, enc);
                        if (cc <= 0xFFFF)
                            clen = 6;  /* \uXXXX */
                        else if (cc <= 0xFFFFF)
                            clen = 9;  /* \u{XXXXX} */
                        else
                            clen = 10; /* \u{XXXXXX} */
                        p += MBCLEN_CHARFOUND_LEN(n)-1;
                        break;
                    }
                }
                clen = 4;       /* \xNN */
            }
            break;
        }

        if (clen > LONG_MAX - len) {
            rb_raise(rb_eRuntimeError, "string size too big");
        }
        len += clen;
    }

    result = rb_str_new(0, len);
    p = RSTRING_PTR(str); pend = p + RSTRING_LEN(str);
    q = RSTRING_PTR(result); qend = q + len + 1;

    *q++ = '"';
    while (p < pend) {
        unsigned char c = *p++;

        if (c == '"' || c == '\\') {
            *q++ = '\\';
            *q++ = c;
        }
        else if (c == '#') {
            if (IS_EVSTR(p, pend)) *q++ = '\\';
            *q++ = '#';
        }
        else if (c == '\n') {
            *q++ = '\\';
            *q++ = 'n';
        }
        else if (c == '\r') {
            *q++ = '\\';
            *q++ = 'r';
        }
        else if (c == '\t') {
            *q++ = '\\';
            *q++ = 't';
        }
        else if (c == '\f') {
            *q++ = '\\';
            *q++ = 'f';
        }
        else if (c == '\013') {
            *q++ = '\\';
            *q++ = 'v';
        }
        else if (c == '\010') {
            *q++ = '\\';
            *q++ = 'b';
        }
        else if (c == '\007') {
            *q++ = '\\';
            *q++ = 'a';
        }
        else if (c == '\033') {
            *q++ = '\\';
            *q++ = 'e';
        }
        else if (ISPRINT(c)) {
            *q++ = c;
        }
        else {
            *q++ = '\\';
            if (u8) {
                int n = rb_enc_precise_mbclen(p-1, pend, enc) - 1;
                if (MBCLEN_CHARFOUND_P(n)) {
                    int cc = rb_enc_mbc_to_codepoint(p-1, pend, enc);
                    p += n;
                    if (cc <= 0xFFFF)
                        snprintf(q, qend-q, "u%04X", cc);    /* \uXXXX */
                    else
                        snprintf(q, qend-q, "u{%X}", cc);  /* \u{XXXXX} or \u{XXXXXX} */
                    q += strlen(q);
                    continue;
                }
            }
            snprintf(q, qend-q, "x%02X", c);
            q += 3;
        }
    }
    *q++ = '"';
    *q = '\0';
    if (!rb_enc_asciicompat(enc)) {
        snprintf(q, qend-q, nonascii_suffix, enc->name);
        encidx = rb_ascii8bit_encindex();
    }
    /* result from dump is ASCII */
    rb_enc_associate_index(result, encidx);
    ENC_CODERANGE_SET(result, ENC_CODERANGE_7BIT);
    return result;
}

Returns a printable version of self, enclosed in double-quotes, with special characters escaped, and with non-printing characters replaced by hexadecimal notation:

"hello \n ''".dump    # => "\"hello \\n ''\""
"\f\x00\xff\\\"".dump # => "\"\\f\\x00\\xFF\\\\\\\"\""

Related: String#undump (inverse of String#dump).

each_byte {|byte| ... } → self

each_byte → enumerator

string.c View on GitHub

          
            static VALUE
rb_str_each_byte(VALUE str)
{
    RETURN_SIZED_ENUMERATOR(str, 0, 0, rb_str_each_byte_size);
    return rb_str_enumerate_bytes(str, 0);
}

Calls the given block with each successive byte from self; returns self:

'hello'.each_byte {|byte| print byte, ' ' }
print "\n"
'тест'.each_byte {|byte| print byte, ' ' }
print "\n"
'こんにちは'.each_byte {|byte| print byte, ' ' }
print "\n"

Output:

104 101 108 108 111
209 130 208 181 209 129 209 130
227 129 147 227 130 147 227 129 171 227 129 161 227 129 175

Returns an enumerator if no block is given.

each_char {|c| ... } → self

each_char → enumerator

string.c View on GitHub

          
            static VALUE
rb_str_each_char(VALUE str)
{
    RETURN_SIZED_ENUMERATOR(str, 0, 0, rb_str_each_char_size);
    return rb_str_enumerate_chars(str, 0);
}

Calls the given block with each successive character from self; returns self:

'hello'.each_char {|char| print char, ' ' }
print "\n"
'тест'.each_char {|char| print char, ' ' }
print "\n"
'こんにちは'.each_char {|char| print char, ' ' }
print "\n"

Output:

h e l l o
т е с т
こ ん に ち は

Returns an enumerator if no block is given.

each_codepoint {|integer| ... } → self

each_codepoint → enumerator

string.c View on GitHub

          
            static VALUE
rb_str_each_codepoint(VALUE str)
{
    RETURN_SIZED_ENUMERATOR(str, 0, 0, rb_str_each_char_size);
    return rb_str_enumerate_codepoints(str, 0);
}

Calls the given block with each successive codepoint from self; each codepoint is the integer value for a character; returns self:

'hello'.each_codepoint {|codepoint| print codepoint, ' ' }
print "\n"
'тест'.each_codepoint {|codepoint| print codepoint, ' ' }
print "\n"
'こんにちは'.each_codepoint {|codepoint| print codepoint, ' ' }
print "\n"

Output:

104 101 108 108 111
1090 1077 1089 1090
12371 12435 12395 12385 12399

Returns an enumerator if no block is given.

each_grapheme_cluster {|gc| ... } → self

each_grapheme_cluster → enumerator

string.c View on GitHub

          
            static VALUE
rb_str_each_grapheme_cluster(VALUE str)
{
    RETURN_SIZED_ENUMERATOR(str, 0, 0, rb_str_each_grapheme_cluster_size);
    return rb_str_enumerate_grapheme_clusters(str, 0);
}

Calls the given block with each successive grapheme cluster from self (see Unicode Grapheme Cluster Boundaries); returns self:

s = "\u0061\u0308-pqr-\u0062\u0308-xyz-\u0063\u0308" # => "ä-pqr-b̈-xyz-c̈"
s.each_grapheme_cluster {|gc| print gc, ' ' }

Output:

ä - p q r - b̈ - x y z - c̈

Returns an enumerator if no block is given.

each_line(line_sep = $/, chomp: false) {|substring| ... } → self

each_line(line_sep = $/, chomp: false) → enumerator

string.c View on GitHub

          
            static VALUE
rb_str_each_line(int argc, VALUE *argv, VALUE str)
{
    RETURN_SIZED_ENUMERATOR(str, argc, argv, 0);
    return rb_str_enumerate_lines(argc, argv, str, 0);
}

With a block given, forms the substrings (“lines”) that are the result of splitting self at each occurrence of the given line separator line_sep; passes each line to the block; returns self:

s = <<~EOT
This is the first line.
This is line two.

This is line four.
This is line five.
EOT

s.each_line {|line| p line }

Output:

"This is the first line.\n"
"This is line two.\n"
"\n"
"This is line four.\n"
"This is line five.\n"

With a different line_sep:

s.each_line(' is ') {|line| p line }

Output:

"This is "
"the first line.\nThis is "
"line two.\n\nThis is "
"line four.\nThis is "
"line five.\n"

With chomp as true, removes the trailing line_sep from each line:

s.each_line(chomp: true) {|line| p line }

Output:

"This is the first line."
"This is line two."
""
"This is line four."
"This is line five."

With an empty string as line_sep, forms and passes “paragraphs” by splitting at each occurrence of two or more newlines:

s.each_line('') {|line| p line }

Output:

"This is the first line.\nThis is line two.\n\n"
"This is line four.\nThis is line five.\n"

With no block given, returns an enumerator.

empty? → true or false

string.c View on GitHub

          
            static VALUE
rb_str_empty(VALUE str)
{
    return RBOOL(RSTRING_LEN(str) == 0);
}

Returns true if the length of self is zero, false otherwise:

"hello".empty? # => false
" ".empty? # => false
"".empty? # => true

encode(dst_encoding = Encoding.default_internal, **enc_opts) → string

encode(dst_encoding, src_encoding, **enc_opts) → string

transcode.c View on GitHub

          
            static VALUE
str_encode(int argc, VALUE *argv, VALUE str)
{
    VALUE newstr = str;
    int encidx = str_transcode(argc, argv, &newstr);
    return encoded_dup(newstr, str, encidx);
}

Returns a copy of self transcoded as determined by dst_encoding. By default, raises an exception if self contains an invalid byte or a character not defined in dst_encoding; that behavior may be modified by encoding options; see below.

With no arguments:

Uses the same encoding if Encoding.default_internal is nil (the default):

Encoding.default_internal # => nil
s = "Ruby\x99".force_encoding('Windows-1252')
s.encoding                # => #<Encoding:Windows-1252>
s.bytes                   # => [82, 117, 98, 121, 153]
t = s.encode              # => "Ruby\x99"
t.encoding                # => #<Encoding:Windows-1252>
t.bytes                   # => [82, 117, 98, 121, 226, 132, 162]

Otherwise, uses the encoding Encoding.default_internal:

Encoding.default_internal = 'UTF-8'
t = s.encode              # => "Ruby™"
t.encoding                # => #<Encoding:UTF-8>

With only argument dst_encoding given, uses that encoding:

s = "Ruby\x99".force_encoding('Windows-1252')
s.encoding            # => #<Encoding:Windows-1252>
t = s.encode('UTF-8') # => "Ruby™"
t.encoding            # => #<Encoding:UTF-8>

With arguments dst_encoding and src_encoding given, interprets self using src_encoding, encodes the new string using dst_encoding:

s = "Ruby\x99"
t = s.encode('UTF-8', 'Windows-1252') # => "Ruby™"
t.encoding                            # => #<Encoding:UTF-8>

Optional keyword arguments enc_opts specify encoding options; see Encoding Options.

Please note that, unless invalid: :replace option is given, conversion from an encoding enc to the same encoding enc (independent of whether enc is given explicitly or implicitly) is a no-op, i.e. the string is simply copied without any changes, and no exceptions are raised, even if there are invalid bytes.

encode!(dst_encoding = Encoding.default_internal, **enc_opts) → self

encode!(dst_encoding, src_encoding, **enc_opts) → self

transcode.c View on GitHub

          
            static VALUE
str_encode_bang(int argc, VALUE *argv, VALUE str)
{
    VALUE newstr;
    int encidx;

    rb_check_frozen(str);

    newstr = str;
    encidx = str_transcode(argc, argv, &newstr);

    if (encidx < 0) return str;
    if (newstr == str) {
        rb_enc_associate_index(str, encidx);
        return str;
    }
    rb_str_shared_replace(str, newstr);
    return str_encode_associate(str, encidx);
}

Like encode, but applies encoding changes to self; returns self.

obj.encoding → encoding

string.c View on GitHub

          
            VALUE
rb_obj_encoding(VALUE obj)
{
    int idx = rb_enc_get_index(obj);
    if (idx < 0) {
        rb_raise(rb_eTypeError, "unknown encoding");
    }
    return rb_enc_from_encoding_index(idx & ENC_INDEX_MASK);
}

Returns the Encoding object that represents the encoding of obj.

end_with?(*strings) → true or false

string.c View on GitHub

          
            static VALUE
rb_str_end_with(int argc, VALUE *argv, VALUE str)
{
    int i;

    for (i=0; i<argc; i++) {
        VALUE tmp = argv[i];
        const char *p, *s, *e;
        long slen, tlen;
        rb_encoding *enc;

        StringValue(tmp);
        enc = rb_enc_check(str, tmp);
        if ((tlen = RSTRING_LEN(tmp)) == 0) return Qtrue;
        if ((slen = RSTRING_LEN(str)) < tlen) continue;
        p = RSTRING_PTR(str);
        e = p + slen;
        s = e - tlen;
        if (!at_char_boundary(p, s, e, enc))
            continue;
        if (memcmp(s, RSTRING_PTR(tmp), tlen) == 0)
            return Qtrue;
    }
    return Qfalse;
}

Returns whether self ends with any of the given strings.

Returns true if any given string matches the end, false otherwise:

'hello'.end_with?('ello')               #=> true
'hello'.end_with?('heaven', 'ello')     #=> true
'hello'.end_with?('heaven', 'paradise') #=> false
'тест'.end_with?('т')                   # => true
'こんにちは'.end_with?('は')              # => true

Related: String#start_with?.

eql?(object) → true or false

string.c View on GitHub

          
            VALUE
rb_str_eql(VALUE str1, VALUE str2)
{
    if (str1 == str2) return Qtrue;
    if (!RB_TYPE_P(str2, T_STRING)) return Qfalse;
    return rb_str_eql_internal(str1, str2);
}

Returns true if object has the same length and content; as self; false otherwise:

s = 'foo'
s.eql?('foo') # => true
s.eql?('food') # => false
s.eql?('FOO') # => false

Returns false if the two strings’ encodings are not compatible:

"\u{e4 f6 fc}".encode("ISO-8859-1").eql?("\u{c4 d6 dc}") # => false

force_encoding(encoding) → self

string.c View on GitHub

          
            static VALUE
rb_str_force_encoding(VALUE str, VALUE enc)
{
    str_modifiable(str);

    rb_encoding *encoding = rb_to_encoding(enc);
    int idx = rb_enc_to_index(encoding);

    // If the encoding is unchanged, we do nothing.
    if (ENCODING_GET(str) == idx) {
        return str;
    }

    rb_enc_associate_index(str, idx);

    // If the coderange was 7bit and the new encoding is ASCII-compatible
    // we can keep the coderange.
    if (ENC_CODERANGE(str) == ENC_CODERANGE_7BIT && encoding && rb_enc_asciicompat(encoding)) {
        return str;
    }

    ENC_CODERANGE_CLEAR(str);
    return str;
}

Changes the encoding of self to encoding, which may be a string encoding name or an Encoding object; returns self:

s = 'łał'
s.bytes                   # => [197, 130, 97, 197, 130]
s.encoding                # => #<Encoding:UTF-8>
s.force_encoding('ascii') # => "\xC5\x82a\xC5\x82"
s.encoding                # => #<Encoding:US-ASCII>

Does not change the underlying bytes:

s.bytes                   # => [197, 130, 97, 197, 130]

Makes the change even if the given encoding is invalid for self (as is the change above):

s.valid_encoding?                 # => false
s.force_encoding(Encoding::UTF_8) # => "łał"
s.valid_encoding?                 # => true

getbyte(index) → integer or nil

string.c View on GitHub

          
            VALUE
rb_str_getbyte(VALUE str, VALUE index)
{
    long pos = NUM2LONG(index);

    if (pos < 0)
        pos += RSTRING_LEN(str);
    if (pos < 0 ||  RSTRING_LEN(str) <= pos)
        return Qnil;

    return INT2FIX((unsigned char)RSTRING_PTR(str)[pos]);
}

Returns the byte at zero-based index as an integer, or nil if index is out of range:

s = 'abcde'   # => "abcde"
s.getbyte(0)  # => 97
s.getbyte(-1) # => 101
s.getbyte(5)  # => nil

Related: String#setbyte.

grapheme_clusters → array_of_grapheme_clusters

string.c View on GitHub

          
            static VALUE
rb_str_grapheme_clusters(VALUE str)
{
    VALUE ary = WANTARRAY("grapheme_clusters", rb_str_strlen(str));
    return rb_str_enumerate_grapheme_clusters(str, ary);
}

Returns an array of the grapheme clusters in self (see Unicode Grapheme Cluster Boundaries):

s = "\u0061\u0308-pqr-\u0062\u0308-xyz-\u0063\u0308" # => "ä-pqr-b̈-xyz-c̈"
s.grapheme_clusters
# => ["ä", "-", "p", "q", "r", "-", "b̈", "-", "x", "y", "z", "-", "c̈"]

gsub(pattern, replacement) → new_string

gsub(pattern) {|match| ... } → new_string

gsub(pattern) → enumerator

string.c View on GitHub

          
            static VALUE
rb_str_gsub(int argc, VALUE *argv, VALUE str)
{
    return str_gsub(argc, argv, str, 0);
}

Returns a copy of self with all occurrences of the given pattern replaced.

See Substitution Methods.

Returns an Enumerator if no replacement and no block given.

gsub!(pattern, replacement) → self or nil

gsub!(pattern) {|match| ... } → self or nil

gsub!(pattern) → an_enumerator

string.c View on GitHub

          
            static VALUE
rb_str_gsub_bang(int argc, VALUE *argv, VALUE str)
{
    str_modify_keep_cr(str);
    return str_gsub(argc, argv, str, 1);
}

Performs the specified substring replacement(s) on self; returns self if any replacement occurred, nil otherwise.

See Substitution Methods.

Returns an Enumerator if no replacement and no block given.

hash → integer

string.c View on GitHub

          
            static VALUE
rb_str_hash_m(VALUE str)
{
    st_index_t hval = rb_str_hash(str);
    return ST2FIX(hval);
}

Returns the integer hash value for self. The value is based on the length, content and encoding of self.

Related: Object#hash.

hex → integer

string.c View on GitHub

          
            static VALUE
rb_str_hex(VALUE str)
{
    return rb_str_to_inum(str, 16, FALSE);
}

Interprets the leading substring of self as a string of hexadecimal digits (with an optional sign and an optional 0x) and returns the corresponding number; returns zero if there is no such leading substring:

'0x0a'.hex        # => 10
'-1234'.hex       # => -4660
'0'.hex           # => 0
'non-numeric'.hex # => 0

Related: String#oct.

include?(other_string) → true or false

string.c View on GitHub

          
            VALUE
rb_str_include(VALUE str, VALUE arg)
{
    long i;

    StringValue(arg);
    i = rb_str_index(str, arg, 0);

    return RBOOL(i != -1);
}

Returns true if self contains other_string, false otherwise:

s = 'foo'
s.include?('f')    # => true
s.include?('fo')   # => true
s.include?('food') # => false

index(substring, offset = 0) → integer or nil

index(regexp, offset = 0) → integer or nil

string.c View on GitHub

          
            static VALUE
rb_str_index_m(int argc, VALUE *argv, VALUE str)
{
    VALUE sub;
    VALUE initpos;
    rb_encoding *enc = STR_ENC_GET(str);
    long pos;

    if (rb_scan_args(argc, argv, "11", &sub, &initpos) == 2) {
        long slen = str_strlen(str, enc); /* str's enc */
        pos = NUM2LONG(initpos);
        if (pos < 0 ? (pos += slen) < 0 : pos > slen) {
            if (RB_TYPE_P(sub, T_REGEXP)) {
                rb_backref_set(Qnil);
            }
            return Qnil;
        }
    }
    else {
        pos = 0;
    }

    if (RB_TYPE_P(sub, T_REGEXP)) {
        pos = str_offset(RSTRING_PTR(str), RSTRING_END(str), pos,
                         enc, single_byte_optimizable(str));

        if (rb_reg_search(sub, str, pos, 0) >= 0) {
            VALUE match = rb_backref_get();
            struct re_registers *regs = RMATCH_REGS(match);
            pos = rb_str_sublen(str, BEG(0));
            return LONG2NUM(pos);
        }
    }
    else {
        StringValue(sub);
        pos = rb_str_index(str, sub, pos);
        if (pos >= 0) {
            pos = rb_str_sublen(str, pos);
            return LONG2NUM(pos);
        }
    }
    return Qnil;
}

Returns the integer index of the first match for the given argument, or nil if none found; the search of self is forward, and begins at position offset (in characters).

With string argument substring, returns the index of the first matching substring in self:

'foo'.index('f')         # => 0
'foo'.index('o')         # => 1
'foo'.index('oo')        # => 1
'foo'.index('ooo')       # => nil
'тест'.index('с')        # => 2
'こんにちは'.index('ち')   # => 3

With Regexp argument regexp, returns the index of the first match in self:

'foo'.index(/o./) # => 1
'foo'.index(/.o/) # => 0

With positive integer offset, begins the search at position offset:

'foo'.index('o', 1)        # => 1
'foo'.index('o', 2)        # => 2
'foo'.index('o', 3)        # => nil
'тест'.index('с', 1)       # => 2
'こんにちは'.index('ち', 2)  # => 3

With negative integer offset, selects the search position by counting backward from the end of self:

'foo'.index('o', -1)  # => 2
'foo'.index('o', -2)  # => 1
'foo'.index('o', -3)  # => 1
'foo'.index('o', -4)  # => nil
'foo'.index(/o./, -2) # => 1
'foo'.index(/.o/, -2) # => 1

Related: String#rindex.

replace(other_string) -> self

string.c View on GitHub

          
            VALUE
rb_str_replace(VALUE str, VALUE str2)
{
    str_modifiable(str);
    if (str == str2) return str;

    StringValue(str2);
    str_discard(str);
    return str_replace(str, str2);
}

Replaces the contents of self with the contents of other_string:

s = 'foo'        # => "foo"
s.replace('bar') # => "bar"

insert(index, other_string) → self

string.c View on GitHub

          
            static VALUE
rb_str_insert(VALUE str, VALUE idx, VALUE str2)
{
    long pos = NUM2LONG(idx);

    if (pos == -1) {
        return rb_str_append(str, str2);
    }
    else if (pos < 0) {
        pos++;
    }
    rb_str_update(str, pos, 0, str2);
    return str;
}

Inserts the given other_string into self; returns self.

If the Integer index is positive, inserts other_string at offset index:

'foo'.insert(1, 'bar') # => "fbaroo"

If the Integer index is negative, counts backward from the end of self and inserts other_string at offset index+1 (that is, after self[index]):

'foo'.insert(-2, 'bar') # => "fobaro"

inspect → string

string.c View on GitHub

          
            VALUE
rb_str_inspect(VALUE str)
{
    int encidx = ENCODING_GET(str);
    rb_encoding *enc = rb_enc_from_index(encidx);
    const char *p, *pend, *prev;
    char buf[CHAR_ESC_LEN + 1];
    VALUE result = rb_str_buf_new(0);
    rb_encoding *resenc = rb_default_internal_encoding();
    int unicode_p = rb_enc_unicode_p(enc);
    int asciicompat = rb_enc_asciicompat(enc);

    if (resenc == NULL) resenc = rb_default_external_encoding();
    if (!rb_enc_asciicompat(resenc)) resenc = rb_usascii_encoding();
    rb_enc_associate(result, resenc);
    str_buf_cat2(result, "\"");

    p = RSTRING_PTR(str); pend = RSTRING_END(str);
    prev = p;
    while (p < pend) {
        unsigned int c, cc;
        int n;

        n = rb_enc_precise_mbclen(p, pend, enc);
        if (!MBCLEN_CHARFOUND_P(n)) {
            if (p > prev) str_buf_cat(result, prev, p - prev);
            n = rb_enc_mbminlen(enc);
            if (pend < p + n)
                n = (int)(pend - p);
            while (n--) {
                snprintf(buf, CHAR_ESC_LEN, "\\x%02X", *p & 0377);
                str_buf_cat(result, buf, strlen(buf));
                prev = ++p;
            }
            continue;
        }
        n = MBCLEN_CHARFOUND_LEN(n);
        c = rb_enc_mbc_to_codepoint(p, pend, enc);
        p += n;
        if ((asciicompat || unicode_p) &&
          (c == '"'|| c == '\\' ||
            (c == '#' &&
             p < pend &&
             MBCLEN_CHARFOUND_P(rb_enc_precise_mbclen(p,pend,enc)) &&
             (cc = rb_enc_codepoint(p,pend,enc),
              (cc == '$' || cc == '@' || cc == '{'))))) {
            if (p - n > prev) str_buf_cat(result, prev, p - n - prev);
            str_buf_cat2(result, "\\");
            if (asciicompat || enc == resenc) {
                prev = p - n;
                continue;
            }
        }
        switch (c) {
          case '\n': cc = 'n'; break;
          case '\r': cc = 'r'; break;
          case '\t': cc = 't'; break;
          case '\f': cc = 'f'; break;
          case '\013': cc = 'v'; break;
          case '\010': cc = 'b'; break;
          case '\007': cc = 'a'; break;
          case 033: cc = 'e'; break;
          default: cc = 0; break;
        }
        if (cc) {
            if (p - n > prev) str_buf_cat(result, prev, p - n - prev);
            buf[0] = '\\';
            buf[1] = (char)cc;
            str_buf_cat(result, buf, 2);
            prev = p;
            continue;
        }
        /* The special casing of 0x85 (NEXT_LINE) here is because
         * Oniguruma historically treats it as printable, but it
         * doesn't match the print POSIX bracket class or character
         * property in regexps.
         *
         * See Ruby Bug #16842 for details:
         * https://bugs.ruby-lang.org/issues/16842
         */
        if ((enc == resenc && rb_enc_isprint(c, enc) && c != 0x85) ||
            (asciicompat && rb_enc_isascii(c, enc) && ISPRINT(c))) {
            continue;
        }
        else {
            if (p - n > prev) str_buf_cat(result, prev, p - n - prev);
            rb_str_buf_cat_escaped_char(result, c, unicode_p);
            prev = p;
            continue;
        }
    }
    if (p > prev) str_buf_cat(result, prev, p - prev);
    str_buf_cat2(result, "\"");

    return result;
}

Returns a printable version of self, enclosed in double-quotes, and with special characters escaped:

s = "foo\tbar\tbaz\n"
s.inspect
# => "\"foo\\tbar\\tbaz\\n\""

str.intern → symbol

string.c View on GitHub

          
            VALUE
rb_str_intern(VALUE str)
{
    VALUE sym;

    GLOBAL_SYMBOLS_ENTER(symbols);
    {
        sym = lookup_str_sym_with_lock(symbols, str);

        if (sym) {
            // ok
        }
        else if (USE_SYMBOL_GC) {
            rb_encoding *enc = rb_enc_get(str);
            rb_encoding *ascii = rb_usascii_encoding();
            if (enc != ascii && sym_check_asciionly(str, false)) {
                str = rb_str_dup(str);
                rb_enc_associate(str, ascii);
                OBJ_FREEZE(str);
                enc = ascii;
            }
            else {
                str = rb_str_dup(str);
                OBJ_FREEZE(str);
            }
            str = rb_fstring(str);
            int type = rb_str_symname_type(str, IDSET_ATTRSET_FOR_INTERN);
            if (type < 0) type = ID_JUNK;
            sym = dsymbol_alloc(symbols, rb_cSymbol, str, enc, type);
        }
        else {
            ID id = intern_str(str, 0);
            sym = ID2SYM(id);
        }
    }
    GLOBAL_SYMBOLS_LEAVE();
    return sym;
}

Returns the Symbol corresponding to str, creating the symbol if it did not previously exist. See Symbol#id2name.

"Koala".intern         #=> :Koala
s = 'cat'.to_sym       #=> :cat
s == :cat              #=> true
s = '@cat'.to_sym      #=> :@cat
s == :@cat             #=> true

This can also be used to create symbols that cannot be represented using the :xxx notation.

'cat and dog'.to_sym   #=> :"cat and dog"

length → integer

string.c View on GitHub

          
            VALUE
rb_str_length(VALUE str)
{
    return LONG2NUM(str_strlen(str, NULL));
}

Returns the count of characters (not bytes) in self:

'foo'.length        # => 3
'тест'.length       # => 4
'こんにちは'.length   # => 5

Contrast with String#bytesize:

'foo'.bytesize        # => 3
'тест'.bytesize       # => 8
'こんにちは'.bytesize   # => 15

lines(Line_sep = $/, chomp: false) → array_of_strings

string.c View on GitHub

          
            static VALUE
rb_str_lines(int argc, VALUE *argv, VALUE str)
{
    VALUE ary = WANTARRAY("lines", 0);
    return rb_str_enumerate_lines(argc, argv, str, ary);
}

Forms substrings (“lines”) of self according to the given arguments (see String#each_line for details); returns the lines in an array.

ljust(size, pad_string = ' ') → new_string

string.c View on GitHub

          
            static VALUE
rb_str_ljust(int argc, VALUE *argv, VALUE str)
{
    return rb_str_justify(argc, argv, str, 'l');
}

Returns a left-justified copy of self.

If integer argument size is greater than the size (in characters) of self, returns a new string of length size that is a copy of self, left justified and padded on the right with pad_string:

'hello'.ljust(10)       # => "hello     "
'  hello'.ljust(10)     # => "  hello   "
'hello'.ljust(10, 'ab') # => "helloababa"
'тест'.ljust(10)        # => "тест      "
'こんにちは'.ljust(10)    # => "こんにちは     "

If size is not greater than the size of self, returns a copy of self:

'hello'.ljust(5)  # => "hello"
'hello'.ljust(1)  # => "hello"

lstrip → new_string

string.c View on GitHub

          
            static VALUE
rb_str_lstrip(VALUE str)
{
    char *start;
    long len, loffset;
    RSTRING_GETMEM(str, start, len);
    loffset = lstrip_offset(str, start, start+len, STR_ENC_GET(str));
    if (loffset <= 0) return str_duplicate(rb_cString, str);
    return rb_str_subseq(str, loffset, len - loffset);
}

Returns a copy of self with leading whitespace removed; see Whitespace in Strings:

whitespace = "\x00\t\n\v\f\r "
s = whitespace + 'abc' + whitespace
s        # => "\u0000\t\n\v\f\r abc\u0000\t\n\v\f\r "
s.lstrip # => "abc\u0000\t\n\v\f\r "

lstrip! → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_lstrip_bang(VALUE str)
{
    rb_encoding *enc;
    char *start, *s;
    long olen, loffset;

    str_modify_keep_cr(str);
    enc = STR_ENC_GET(str);
    RSTRING_GETMEM(str, start, olen);
    loffset = lstrip_offset(str, start, start+olen, enc);
    if (loffset > 0) {
        long len = olen-loffset;
        s = start + loffset;
        memmove(start, s, len);
        STR_SET_LEN(str, len);
        TERM_FILL(start+len, rb_enc_mbminlen(enc));
        return str;
    }
    return Qnil;
}

Like String#lstrip, except that any modifications are made in self; returns self if any modification are made, nil otherwise.

match(pattern, offset = 0) → matchdata or nil

match(pattern, offset = 0) {|matchdata| ... } → object

string.c View on GitHub

          
            static VALUE
rb_str_match_m(int argc, VALUE *argv, VALUE str)
{
    VALUE re, result;
    if (argc < 1)
        rb_check_arity(argc, 1, 2);
    re = argv[0];
    argv[0] = str;
    result = rb_funcallv(get_pat(re), rb_intern("match"), argc, argv);
    if (!NIL_P(result) && rb_block_given_p()) {
        return rb_yield(result);
    }
    return result;
}

Returns a MatchData object (or nil) based on self and the given pattern.

Note: also updates Global Variables at Regexp.

Computes regexp by converting pattern (if not already a Regexp).
```
regexp = Regexp.new(pattern)
```
Computes matchdata, which will be either a MatchData object or nil (see Regexp#match):
```
matchdata = <tt>regexp.match(self)
```

With no block given, returns the computed matchdata:

'foo'.match('f') # => #<MatchData "f">
'foo'.match('o') # => #<MatchData "o">
'foo'.match('x') # => nil

If Integer argument offset is given, the search begins at index offset:

'foo'.match('f', 1) # => nil
'foo'.match('o', 1) # => #<MatchData "o">

With a block given, calls the block with the computed matchdata and returns the block’s return value:

'foo'.match(/o/) {|matchdata| matchdata } # => #<MatchData "o">
'foo'.match(/x/) {|matchdata| matchdata } # => nil
'foo'.match(/f/, 1) {|matchdata| matchdata } # => nil

match?(pattern, offset = 0) → true or false

string.c View on GitHub

          
            static VALUE
rb_str_match_m_p(int argc, VALUE *argv, VALUE str)
{
    VALUE re;
    rb_check_arity(argc, 1, 2);
    re = get_pat(argv[0]);
    return rb_reg_match_p(re, str, argc > 1 ? NUM2LONG(argv[1]) : 0);
}

Returns true or false based on whether a match is found for self and pattern.

Note: does not update Global Variables at Regexp.

Computes regexp by converting pattern (if not already a Regexp).

regexp = Regexp.new(pattern)

Returns true if self+.match(regexp) returns a MatchData object, false otherwise:

'foo'.match?(/o/) # => true
'foo'.match?('o') # => true
'foo'.match?(/x/) # => false

If Integer argument offset is given, the search begins at index offset:

'foo'.match?('f', 1) # => false
'foo'.match?('o', 1) # => true

string.c View on GitHub

An alias for succ

next!

string.c View on GitHub

An alias for succ!

oct → integer

string.c View on GitHub

          
            static VALUE
rb_str_oct(VALUE str)
{
    return rb_str_to_inum(str, -8, FALSE);
}

Interprets the leading substring of self as a string of octal digits (with an optional sign) and returns the corresponding number; returns zero if there is no such leading substring:

'123'.oct             # => 83
'-377'.oct            # => -255
'0377non-numeric'.oct # => 255
'non-numeric'.oct     # => 0

If self starts with 0, radix indicators are honored; see Kernel#Integer.

Related: String#hex.

ord → integer

string.c View on GitHub

          
            static VALUE
rb_str_ord(VALUE s)
{
    unsigned int c;

    c = rb_enc_codepoint(RSTRING_PTR(s), RSTRING_END(s), STR_ENC_GET(s));
    return UINT2NUM(c);
}

Returns the integer ordinal of the first character of self:

'h'.ord         # => 104
'hello'.ord     # => 104
'тест'.ord      # => 1090
'こんにちは'.ord  # => 12371

partition(string_or_regexp) → [head, match, tail]

string.c View on GitHub

          
            static VALUE
rb_str_partition(VALUE str, VALUE sep)
{
    long pos;

    sep = get_pat_quoted(sep, 0);
    if (RB_TYPE_P(sep, T_REGEXP)) {
        if (rb_reg_search(sep, str, 0, 0) < 0) {
            goto failed;
        }
        VALUE match = rb_backref_get();
        struct re_registers *regs = RMATCH_REGS(match);

        pos = BEG(0);
        sep = rb_str_subseq(str, pos, END(0) - pos);
    }
    else {
        pos = rb_str_index(str, sep, 0);
        if (pos < 0) goto failed;
    }
    return rb_ary_new3(3, rb_str_subseq(str, 0, pos),
                          sep,
                          rb_str_subseq(str, pos+RSTRING_LEN(sep),
                                             RSTRING_LEN(str)-pos-RSTRING_LEN(sep)));

  failed:
    return rb_ary_new3(3, str_duplicate(rb_cString, str), str_new_empty_String(str), str_new_empty_String(str));
}

Returns a 3-element array of substrings of self.

Matches a pattern against self, scanning from the beginning. The pattern is:

string_or_regexp itself, if it is a Regexp.
Regexp.quote(string_or_regexp), if string_or_regexp is a string.

If the pattern is matched, returns pre-match, first-match, post-match:

'hello'.partition('l')      # => ["he", "l", "lo"]
'hello'.partition('ll')     # => ["he", "ll", "o"]
'hello'.partition('h')      # => ["", "h", "ello"]
'hello'.partition('o')      # => ["hell", "o", ""]
'hello'.partition(/l+/)     #=> ["he", "ll", "o"]
'hello'.partition('')       # => ["", "", "hello"]
'тест'.partition('т')       # => ["", "т", "ест"]
'こんにちは'.partition('に')  # => ["こん", "に", "ちは"]

If the pattern is not matched, returns a copy of self and two empty strings:

'hello'.partition('x') # => ["hello", "", ""]

prepend(*other_strings) → string

string.c View on GitHub

          
            static VALUE
rb_str_prepend_multi(int argc, VALUE *argv, VALUE str)
{
    str_modifiable(str);

    if (argc == 1) {
        rb_str_update(str, 0L, 0L, argv[0]);
    }
    else if (argc > 1) {
        int i;
        VALUE arg_str = rb_str_tmp_new(0);
        rb_enc_copy(arg_str, str);
        for (i = 0; i < argc; i++) {
            rb_str_append(arg_str, argv[i]);
        }
        rb_str_update(str, 0L, 0L, arg_str);
    }

    return str;
}

Prepends each string in other_strings to self and returns self:

s = 'foo'
s.prepend('bar', 'baz') # => "barbazfoo"
s                       # => "barbazfoo"

Related: String#concat.

replace(other_string) → self

string.c View on GitHub

An alias for initialize_copy

reverse → string

string.c View on GitHub

          
            static VALUE
rb_str_reverse(VALUE str)
{
    rb_encoding *enc;
    VALUE rev;
    char *s, *e, *p;
    int cr;

    if (RSTRING_LEN(str) <= 1) return str_duplicate(rb_cString, str);
    enc = STR_ENC_GET(str);
    rev = rb_str_new(0, RSTRING_LEN(str));
    s = RSTRING_PTR(str); e = RSTRING_END(str);
    p = RSTRING_END(rev);
    cr = ENC_CODERANGE(str);

    if (RSTRING_LEN(str) > 1) {
        if (single_byte_optimizable(str)) {
            while (s < e) {
                *--p = *s++;
            }
        }
        else if (cr == ENC_CODERANGE_VALID) {
            while (s < e) {
                int clen = rb_enc_fast_mbclen(s, e, enc);

                p -= clen;
                memcpy(p, s, clen);
                s += clen;
            }
        }
        else {
            cr = rb_enc_asciicompat(enc) ?
                ENC_CODERANGE_7BIT : ENC_CODERANGE_VALID;
            while (s < e) {
                int clen = rb_enc_mbclen(s, e, enc);

                if (clen > 1 || (*s & 0x80)) cr = ENC_CODERANGE_UNKNOWN;
                p -= clen;
                memcpy(p, s, clen);
                s += clen;
            }
        }
    }
    STR_SET_LEN(rev, RSTRING_LEN(str));
    str_enc_copy_direct(rev, str);
    ENC_CODERANGE_SET(rev, cr);

    return rev;
}

Returns a new string with the characters from self in reverse order.

'stressed'.reverse # => "desserts"

reverse! → self

string.c View on GitHub

          
            static VALUE
rb_str_reverse_bang(VALUE str)
{
    if (RSTRING_LEN(str) > 1) {
        if (single_byte_optimizable(str)) {
            char *s, *e, c;

            str_modify_keep_cr(str);
            s = RSTRING_PTR(str);
            e = RSTRING_END(str) - 1;
            while (s < e) {
                c = *s;
                *s++ = *e;
                *e-- = c;
            }
        }
        else {
            str_shared_replace(str, rb_str_reverse(str));
        }
    }
    else {
        str_modify_keep_cr(str);
    }
    return str;
}

Returns self with its characters reversed:

s = 'stressed'
s.reverse! # => "desserts"
s          # => "desserts"

rindex(substring, offset = self.length) → integer or nil

rindex(regexp, offset = self.length) → integer or nil

string.c View on GitHub

          
            static VALUE
rb_str_rindex_m(int argc, VALUE *argv, VALUE str)
{
    VALUE sub;
    VALUE initpos;
    rb_encoding *enc = STR_ENC_GET(str);
    long pos, len = str_strlen(str, enc); /* str's enc */

    if (rb_scan_args(argc, argv, "11", &sub, &initpos) == 2) {
        pos = NUM2LONG(initpos);
        if (pos < 0 && (pos += len) < 0) {
            if (RB_TYPE_P(sub, T_REGEXP)) {
                rb_backref_set(Qnil);
            }
            return Qnil;
        }
        if (pos > len) pos = len;
    }
    else {
        pos = len;
    }

    if (RB_TYPE_P(sub, T_REGEXP)) {
        /* enc = rb_enc_check(str, sub); */
        pos = str_offset(RSTRING_PTR(str), RSTRING_END(str), pos,
                         enc, single_byte_optimizable(str));

        if (rb_reg_search(sub, str, pos, 1) >= 0) {
            VALUE match = rb_backref_get();
            struct re_registers *regs = RMATCH_REGS(match);
            pos = rb_str_sublen(str, BEG(0));
            return LONG2NUM(pos);
        }
    }
    else {
        StringValue(sub);
        pos = rb_str_rindex(str, sub, pos);
        if (pos >= 0) {
            pos = rb_str_sublen(str, pos);
            return LONG2NUM(pos);
        }
    }
    return Qnil;
}

Returns the Integer index of the last occurrence of the given substring, or nil if none found:

'foo'.rindex('f') # => 0
'foo'.rindex('o') # => 2
'foo'.rindex('oo') # => 1
'foo'.rindex('ooo') # => nil

Returns the Integer index of the last match for the given Regexp regexp, or nil if none found:

'foo'.rindex(/f/) # => 0
'foo'.rindex(/o/) # => 2
'foo'.rindex(/oo/) # => 1
'foo'.rindex(/ooo/) # => nil

The last match means starting at the possible last position, not the last of longest matches.

'foo'.rindex(/o+/) # => 2
$~ #=> #<MatchData "o">

To get the last longest match, needs to combine with negative lookbehind.

'foo'.rindex(/(?<!o)o+/) # => 1
$~ #=> #<MatchData "oo">

Or String#index with negative lookforward.

'foo'.index(/o+(?!.*o)/) # => 1
$~ #=> #<MatchData "oo">

Integer argument offset, if given and non-negative, specifies the maximum starting position in the

string to _end_ the search:

 'foo'.rindex('o', 0) # => nil
 'foo'.rindex('o', 1) # => 1
 'foo'.rindex('o', 2) # => 2
 'foo'.rindex('o', 3) # => 2

If offset is a negative Integer, the maximum starting position in the string to end the search is the sum of the string’s length and offset:

'foo'.rindex('o', -1) # => 2
'foo'.rindex('o', -2) # => 1
'foo'.rindex('o', -3) # => nil
'foo'.rindex('o', -4) # => nil

Related: String#index.

rjust(size, pad_string = ' ') → new_string

string.c View on GitHub

          
            static VALUE
rb_str_rjust(int argc, VALUE *argv, VALUE str)
{
    return rb_str_justify(argc, argv, str, 'r');
}

Returns a right-justified copy of self.

If integer argument size is greater than the size (in characters) of self, returns a new string of length size that is a copy of self, right justified and padded on the left with pad_string:

'hello'.rjust(10)       # => "     hello"
'hello  '.rjust(10)     # => "   hello  "
'hello'.rjust(10, 'ab') # => "ababahello"
'тест'.rjust(10)        # => "      тест"
'こんにちは'.rjust(10)    # => "     こんにちは"

If size is not greater than the size of self, returns a copy of self:

'hello'.rjust(5, 'ab')  # => "hello"
'hello'.rjust(1, 'ab')  # => "hello"

rpartition(sep) → [head, match, tail]

string.c View on GitHub

          
            static VALUE
rb_str_rpartition(VALUE str, VALUE sep)
{
    long pos = RSTRING_LEN(str);

    sep = get_pat_quoted(sep, 0);
    if (RB_TYPE_P(sep, T_REGEXP)) {
        if (rb_reg_search(sep, str, pos, 1) < 0) {
            goto failed;
        }
        VALUE match = rb_backref_get();
        struct re_registers *regs = RMATCH_REGS(match);

        pos = BEG(0);
        sep = rb_str_subseq(str, pos, END(0) - pos);
    }
    else {
        pos = rb_str_sublen(str, pos);
        pos = rb_str_rindex(str, sep, pos);
        if (pos < 0) {
            goto failed;
        }
    }

    return rb_ary_new3(3, rb_str_subseq(str, 0, pos),
                          sep,
                          rb_str_subseq(str, pos+RSTRING_LEN(sep),
                                        RSTRING_LEN(str)-pos-RSTRING_LEN(sep)));
  failed:
    return rb_ary_new3(3, str_new_empty_String(str), str_new_empty_String(str), str_duplicate(rb_cString, str));
}

Returns a 3-element array of substrings of self.

Matches a pattern against self, scanning backwards from the end. The pattern is:

string_or_regexp itself, if it is a Regexp.
Regexp.quote(string_or_regexp), if string_or_regexp is a string.

If the pattern is matched, returns pre-match, last-match, post-match:

'hello'.rpartition('l')      # => ["hel", "l", "o"]
'hello'.rpartition('ll')     # => ["he", "ll", "o"]
'hello'.rpartition('h')      # => ["", "h", "ello"]
'hello'.rpartition('o')      # => ["hell", "o", ""]
'hello'.rpartition(/l+/)     # => ["hel", "l", "o"]
'hello'.rpartition('')       # => ["hello", "", ""]
'тест'.rpartition('т')       # => ["тес", "т", ""]
'こんにちは'.rpartition('に')  # => ["こん", "に", "ちは"]

If the pattern is not matched, returns two empty strings and a copy of self:

'hello'.rpartition('x') # => ["", "", "hello"]

rstrip → new_string

string.c View on GitHub

          
            static VALUE
rb_str_rstrip(VALUE str)
{
    rb_encoding *enc;
    char *start;
    long olen, roffset;

    enc = STR_ENC_GET(str);
    RSTRING_GETMEM(str, start, olen);
    roffset = rstrip_offset(str, start, start+olen, enc);

    if (roffset <= 0) return str_duplicate(rb_cString, str);
    return rb_str_subseq(str, 0, olen-roffset);
}

Returns a copy of the receiver with trailing whitespace removed; see Whitespace in Strings:

whitespace = "\x00\t\n\v\f\r "
s = whitespace + 'abc' + whitespace
s        # => "\u0000\t\n\v\f\r abc\u0000\t\n\v\f\r "
s.rstrip # => "\u0000\t\n\v\f\r abc"

rstrip! → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_rstrip_bang(VALUE str)
{
    rb_encoding *enc;
    char *start;
    long olen, roffset;

    str_modify_keep_cr(str);
    enc = STR_ENC_GET(str);
    RSTRING_GETMEM(str, start, olen);
    roffset = rstrip_offset(str, start, start+olen, enc);
    if (roffset > 0) {
        long len = olen - roffset;

        STR_SET_LEN(str, len);
        TERM_FILL(start+len, rb_enc_mbminlen(enc));
        return str;
    }
    return Qnil;
}

Like String#rstrip, except that any modifications are made in self; returns self if any modification are made, nil otherwise.

scan(string_or_regexp) → array

scan(string_or_regexp) {|matches| ... } → self

string.c View on GitHub

          
            static VALUE
rb_str_scan(VALUE str, VALUE pat)
{
    VALUE result;
    long start = 0;
    long last = -1, prev = 0;
    char *p = RSTRING_PTR(str); long len = RSTRING_LEN(str);

    pat = get_pat_quoted(pat, 1);
    mustnot_broken(str);
    if (!rb_block_given_p()) {
        VALUE ary = rb_ary_new();

        while (!NIL_P(result = scan_once(str, pat, &start, 0))) {
            last = prev;
            prev = start;
            rb_ary_push(ary, result);
        }
        if (last >= 0) rb_pat_search(pat, str, last, 1);
        else rb_backref_set(Qnil);
        return ary;
    }

    while (!NIL_P(result = scan_once(str, pat, &start, 1))) {
        last = prev;
        prev = start;
        rb_yield(result);
        str_mod_check(str, p, len);
    }
    if (last >= 0) rb_pat_search(pat, str, last, 1);
    return str;
}

Matches a pattern against self; the pattern is:

string_or_regexp itself, if it is a Regexp.
Regexp.quote(string_or_regexp), if string_or_regexp is a string.

Iterates through self, generating a collection of matching results:

If the pattern contains no groups, each result is the matched string, $&.
If the pattern contains groups, each result is an array containing one entry per group.

With no block given, returns an array of the results:

s = 'cruel world'
s.scan(/\w+/)      # => ["cruel", "world"]
s.scan(/.../)      # => ["cru", "el ", "wor"]
s.scan(/(...)/)    # => [["cru"], ["el "], ["wor"]]
s.scan(/(..)(..)/) # => [["cr", "ue"], ["l ", "wo"]]

With a block given, calls the block with each result; returns self:

s.scan(/\w+/) {|w| print "<<#{w}>> " }
print "\n"
s.scan(/(.)(.)/) {|x,y| print y, x }
print "\n"

Output:

<<cruel>> <<world>>
rceu lowlr

scrub(replacement_string = default_replacement) → new_string

scrub{|bytes| ... } → new_string

string.c View on GitHub

          
            static VALUE
str_scrub(int argc, VALUE *argv, VALUE str)
{
    VALUE repl = argc ? (rb_check_arity(argc, 0, 1), argv[0]) : Qnil;
    VALUE new = rb_str_scrub(str, repl);
    return NIL_P(new) ? str_duplicate(rb_cString, str): new;
}

Returns a copy of self with each invalid byte sequence replaced by the given replacement_string.

With no block given and no argument, replaces each invalid sequence with the default replacement string ("�" for a Unicode encoding, '?' otherwise):

s = "foo\x81\x81bar"
s.scrub # => "foo��bar"

With no block given and argument replacement_string given, replaces each invalid sequence with that string:

"foo\x81\x81bar".scrub('xyzzy') # => "fooxyzzyxyzzybar"

With a block given, replaces each invalid sequence with the value of the block:

"foo\x81\x81bar".scrub {|bytes| p bytes; 'XYZZY' }
# => "fooXYZZYXYZZYbar"

Output:

"\x81"
"\x81"

scrub! → self

scrub!(replacement_string = default_replacement) → self

scrub!{|bytes| ... } → self

string.c View on GitHub

          
            static VALUE
str_scrub_bang(int argc, VALUE *argv, VALUE str)
{
    VALUE repl = argc ? (rb_check_arity(argc, 0, 1), argv[0]) : Qnil;
    VALUE new = rb_str_scrub(str, repl);
    if (!NIL_P(new)) rb_str_replace(str, new);
    return str;
}

Like String#scrub, except that any replacements are made in self.

setbyte(index, integer) → integer

string.c View on GitHub

          
            VALUE
rb_str_setbyte(VALUE str, VALUE index, VALUE value)
{
    long pos = NUM2LONG(index);
    long len = RSTRING_LEN(str);
    char *ptr, *head, *left = 0;
    rb_encoding *enc;
    int cr = ENC_CODERANGE_UNKNOWN, width, nlen;

    if (pos < -len || len <= pos)
        rb_raise(rb_eIndexError, "index %ld out of string", pos);
    if (pos < 0)
        pos += len;

    VALUE v = rb_to_int(value);
    VALUE w = rb_int_and(v, INT2FIX(0xff));
    char byte = (char)(NUM2INT(w) & 0xFF);

    if (!str_independent(str))
        str_make_independent(str);
    enc = STR_ENC_GET(str);
    head = RSTRING_PTR(str);
    ptr = &head[pos];
    if (!STR_EMBED_P(str)) {
        cr = ENC_CODERANGE(str);
        switch (cr) {
          case ENC_CODERANGE_7BIT:
            left = ptr;
            *ptr = byte;
            if (ISASCII(byte)) goto end;
            nlen = rb_enc_precise_mbclen(left, head+len, enc);
            if (!MBCLEN_CHARFOUND_P(nlen))
                ENC_CODERANGE_SET(str, ENC_CODERANGE_BROKEN);
            else
                ENC_CODERANGE_SET(str, ENC_CODERANGE_VALID);
            goto end;
          case ENC_CODERANGE_VALID:
            left = rb_enc_left_char_head(head, ptr, head+len, enc);
            width = rb_enc_precise_mbclen(left, head+len, enc);
            *ptr = byte;
            nlen = rb_enc_precise_mbclen(left, head+len, enc);
            if (!MBCLEN_CHARFOUND_P(nlen))
                ENC_CODERANGE_SET(str, ENC_CODERANGE_BROKEN);
            else if (MBCLEN_CHARFOUND_LEN(nlen) != width || ISASCII(byte))
                ENC_CODERANGE_CLEAR(str);
            goto end;
        }
    }
    ENC_CODERANGE_CLEAR(str);
    *ptr = byte;

  end:
    return value;
}

Sets the byte at zero-based index to integer; returns integer:

s = 'abcde'      # => "abcde"
s.setbyte(0, 98) # => 98
s                # => "bbcde"

Related: String#getbyte.

str.shellescape => string

lib/shellwords.rb View on GitHub

          
            # File tmp/rubies/ruby-3.4.0-preview1/lib/shellwords.rb, line 226
def shellescape
  Shellwords.escape(self)
end

Escapes str so that it can be safely used in a Bourne shell command line.

See Shellwords.shellescape for details.

str.shellsplit => array

lib/shellwords.rb View on GitHub

          
            # File tmp/rubies/ruby-3.4.0-preview1/lib/shellwords.rb, line 215
def shellsplit
  Shellwords.split(self)
end

Splits str into an array of tokens in the same way the UNIX Bourne shell does.

See Shellwords.shellsplit for details.

size

string.c View on GitHub

An alias for length

slice(*args)

string.c View on GitHub

An alias for []

slice!(index) → new_string or nil

slice!(start, length) → new_string or nil

slice!(range) → new_string or nil

slice!(regexp, capture = 0) → new_string or nil

slice!(substring) → new_string or nil

string.c View on GitHub

          
            static VALUE
rb_str_slice_bang(int argc, VALUE *argv, VALUE str)
{
    VALUE result = Qnil;
    VALUE indx;
    long beg, len = 1;
    char *p;

    rb_check_arity(argc, 1, 2);
    str_modify_keep_cr(str);
    indx = argv[0];
    if (RB_TYPE_P(indx, T_REGEXP)) {
        if (rb_reg_search(indx, str, 0, 0) < 0) return Qnil;
        VALUE match = rb_backref_get();
        struct re_registers *regs = RMATCH_REGS(match);
        int nth = 0;
        if (argc > 1 && (nth = rb_reg_backref_number(match, argv[1])) < 0) {
            if ((nth += regs->num_regs) <= 0) return Qnil;
        }
        else if (nth >= regs->num_regs) return Qnil;
        beg = BEG(nth);
        len = END(nth) - beg;
        goto subseq;
    }
    else if (argc == 2) {
        beg = NUM2LONG(indx);
        len = NUM2LONG(argv[1]);
        goto num_index;
    }
    else if (FIXNUM_P(indx)) {
        beg = FIX2LONG(indx);
        if (!(p = rb_str_subpos(str, beg, &len))) return Qnil;
        if (!len) return Qnil;
        beg = p - RSTRING_PTR(str);
        goto subseq;
    }
    else if (RB_TYPE_P(indx, T_STRING)) {
        beg = rb_str_index(str, indx, 0);
        if (beg == -1) return Qnil;
        len = RSTRING_LEN(indx);
        result = str_duplicate(rb_cString, indx);
        goto squash;
    }
    else {
        switch (rb_range_beg_len(indx, &beg, &len, str_strlen(str, NULL), 0)) {
          case Qnil:
            return Qnil;
          case Qfalse:
            beg = NUM2LONG(indx);
            if (!(p = rb_str_subpos(str, beg, &len))) return Qnil;
            if (!len) return Qnil;
            beg = p - RSTRING_PTR(str);
            goto subseq;
          default:
            goto num_index;
        }
    }

  num_index:
    if (!(p = rb_str_subpos(str, beg, &len))) return Qnil;
    beg = p - RSTRING_PTR(str);

  subseq:
    result = rb_str_new(RSTRING_PTR(str)+beg, len);
    rb_enc_cr_str_copy_for_substr(result, str);

  squash:
    if (len > 0) {
        if (beg == 0) {
            rb_str_drop_bytes(str, len);
        }
        else {
            char *sptr = RSTRING_PTR(str);
            long slen = RSTRING_LEN(str);
            if (beg + len > slen) /* pathological check */
                len = slen - beg;
            memmove(sptr + beg,
                    sptr + beg + len,
                    slen - (beg + len));
            slen -= len;
            STR_SET_LEN(str, slen);
            TERM_FILL(&sptr[slen], TERM_LEN(str));
        }
    }
    return result;
}

Removes and returns the substring of self specified by the arguments. See String Slices.

A few examples:

string = "This is a string"
string.slice!(2)        #=> "i"
string.slice!(3..6)     #=> " is "
string.slice!(/s.*t/)   #=> "sa st"
string.slice!("r")      #=> "r"
string                  #=> "Thing"

split(field_sep = $;, limit = nil) → array

split(field_sep = $;, limit = nil) {|substring| ... } → self

string.c View on GitHub

          
            static VALUE
rb_str_split_m(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    VALUE spat;
    VALUE limit;
    split_type_t split_type;
    long beg, end, i = 0, empty_count = -1;
    int lim = 0;
    VALUE result, tmp;

    result = rb_block_given_p() ? Qfalse : Qnil;
    if (rb_scan_args(argc, argv, "02", &spat, &limit) == 2) {
        lim = NUM2INT(limit);
        if (lim <= 0) limit = Qnil;
        else if (lim == 1) {
            if (RSTRING_LEN(str) == 0)
                return result ? rb_ary_new2(0) : str;
            tmp = str_duplicate(rb_cString, str);
            if (!result) {
                rb_yield(tmp);
                return str;
            }
            return rb_ary_new3(1, tmp);
        }
        i = 1;
    }
    if (NIL_P(limit) && !lim) empty_count = 0;

    enc = STR_ENC_GET(str);
    split_type = SPLIT_TYPE_REGEXP;
    if (!NIL_P(spat)) {
        spat = get_pat_quoted(spat, 0);
    }
    else if (NIL_P(spat = rb_fs)) {
        split_type = SPLIT_TYPE_AWK;
    }
    else if (!(spat = rb_fs_check(spat))) {
        rb_raise(rb_eTypeError, "value of $; must be String or Regexp");
    }
    else {
        rb_category_warn(RB_WARN_CATEGORY_DEPRECATED, "$; is set to non-nil value");
    }
    if (split_type != SPLIT_TYPE_AWK) {
        switch (BUILTIN_TYPE(spat)) {
          case T_REGEXP:
            rb_reg_options(spat); /* check if uninitialized */
            tmp = RREGEXP_SRC(spat);
            split_type = literal_split_pattern(tmp, SPLIT_TYPE_REGEXP);
            if (split_type == SPLIT_TYPE_AWK) {
                spat = tmp;
                split_type = SPLIT_TYPE_STRING;
            }
            break;

          case T_STRING:
            mustnot_broken(spat);
            split_type = literal_split_pattern(spat, SPLIT_TYPE_STRING);
            break;

          default:
            UNREACHABLE_RETURN(Qnil);
        }
    }

#define SPLIT_STR(beg, len) (empty_count = split_string(result, str, beg, len, empty_count))

    beg = 0;
    char *ptr = RSTRING_PTR(str);
    char *eptr = RSTRING_END(str);
    if (split_type == SPLIT_TYPE_AWK) {
        char *bptr = ptr;
        int skip = 1;
        unsigned int c;

        if (result) result = rb_ary_new();
        end = beg;
        if (is_ascii_string(str)) {
            while (ptr < eptr) {
                c = (unsigned char)*ptr++;
                if (skip) {
                    if (ascii_isspace(c)) {
                        beg = ptr - bptr;
                    }
                    else {
                        end = ptr - bptr;
                        skip = 0;
                        if (!NIL_P(limit) && lim <= i) break;
                    }
                }
                else if (ascii_isspace(c)) {
                    SPLIT_STR(beg, end-beg);
                    skip = 1;
                    beg = ptr - bptr;
                    if (!NIL_P(limit)) ++i;
                }
                else {
                    end = ptr - bptr;
                }
            }
        }
        else {
            while (ptr < eptr) {
                int n;

                c = rb_enc_codepoint_len(ptr, eptr, &n, enc);
                ptr += n;
                if (skip) {
                    if (rb_isspace(c)) {
                        beg = ptr - bptr;
                    }
                    else {
                        end = ptr - bptr;
                        skip = 0;
                        if (!NIL_P(limit) && lim <= i) break;
                    }
                }
                else if (rb_isspace(c)) {
                    SPLIT_STR(beg, end-beg);
                    skip = 1;
                    beg = ptr - bptr;
                    if (!NIL_P(limit)) ++i;
                }
                else {
                    end = ptr - bptr;
                }
            }
        }
    }
    else if (split_type == SPLIT_TYPE_STRING) {
        char *str_start = ptr;
        char *substr_start = ptr;
        char *sptr = RSTRING_PTR(spat);
        long slen = RSTRING_LEN(spat);

        if (result) result = rb_ary_new();
        mustnot_broken(str);
        enc = rb_enc_check(str, spat);
        while (ptr < eptr &&
               (end = rb_memsearch(sptr, slen, ptr, eptr - ptr, enc)) >= 0) {
            /* Check we are at the start of a char */
            char *t = rb_enc_right_char_head(ptr, ptr + end, eptr, enc);
            if (t != ptr + end) {
                ptr = t;
                continue;
            }
            SPLIT_STR(substr_start - str_start, (ptr+end) - substr_start);
            ptr += end + slen;
            substr_start = ptr;
            if (!NIL_P(limit) && lim <= ++i) break;
        }
        beg = ptr - str_start;
    }
    else if (split_type == SPLIT_TYPE_CHARS) {
        char *str_start = ptr;
        int n;

        if (result) result = rb_ary_new_capa(RSTRING_LEN(str));
        mustnot_broken(str);
        enc = rb_enc_get(str);
        while (ptr < eptr &&
               (n = rb_enc_precise_mbclen(ptr, eptr, enc)) > 0) {
            SPLIT_STR(ptr - str_start, n);
            ptr += n;
            if (!NIL_P(limit) && lim <= ++i) break;
        }
        beg = ptr - str_start;
    }
    else {
        if (result) result = rb_ary_new();
        long len = RSTRING_LEN(str);
        long start = beg;
        long idx;
        int last_null = 0;
        struct re_registers *regs;
        VALUE match = 0;

        for (; rb_reg_search(spat, str, start, 0) >= 0;
             (match ? (rb_match_unbusy(match), rb_backref_set(match)) : (void)0)) {
            match = rb_backref_get();
            if (!result) rb_match_busy(match);
            regs = RMATCH_REGS(match);
            end = BEG(0);
            if (start == end && BEG(0) == END(0)) {
                if (!ptr) {
                    SPLIT_STR(0, 0);
                    break;
                }
                else if (last_null == 1) {
                    SPLIT_STR(beg, rb_enc_fast_mbclen(ptr+beg, eptr, enc));
                    beg = start;
                }
                else {
                    if (start == len)
                        start++;
                    else
                        start += rb_enc_fast_mbclen(ptr+start,eptr,enc);
                    last_null = 1;
                    continue;
                }
            }
            else {
                SPLIT_STR(beg, end-beg);
                beg = start = END(0);
            }
            last_null = 0;

            for (idx=1; idx < regs->num_regs; idx++) {
                if (BEG(idx) == -1) continue;
                SPLIT_STR(BEG(idx), END(idx)-BEG(idx));
            }
            if (!NIL_P(limit) && lim <= ++i) break;
        }
        if (match) rb_match_unbusy(match);
    }
    if (RSTRING_LEN(str) > 0 && (!NIL_P(limit) || RSTRING_LEN(str) > beg || lim < 0)) {
        SPLIT_STR(beg, RSTRING_LEN(str)-beg);
    }

    return result ? result : str;
}

Returns an array of substrings of self that are the result of splitting self at each occurrence of the given field separator field_sep.

When field_sep is $;:

If $; is nil (its default value), the split occurs just as if field_sep were given as a space character (see below).
If $; is a string, the split occurs just as if field_sep were given as that string (see below).

When field_sep is ' ' and limit is nil, the split occurs at each sequence of whitespace:

'abc def ghi'.split(' ')         => ["abc", "def", "ghi"]
"abc \n\tdef\t\n  ghi".split(' ') # => ["abc", "def", "ghi"]
'abc  def   ghi'.split(' ')      => ["abc", "def", "ghi"]
''.split(' ')                    => []

When field_sep is a string different from ' ' and limit is nil, the split occurs at each occurrence of field_sep; trailing empty substrings are not returned:

'abracadabra'.split('ab')  => ["", "racad", "ra"]
'aaabcdaaa'.split('a')     => ["", "", "", "bcd"]
''.split('a')              => []
'3.14159'.split('1')       => ["3.", "4", "59"]
'!@#$%^$&*($)_+'.split('$') # => ["!@#", "%^", "&*(", ")_+"]
'тест'.split('т')          => ["", "ес"]
'こんにちは'.split('に')     => ["こん", "ちは"]

When field_sep is a Regexp and limit is nil, the split occurs at each occurrence of a match; trailing empty substrings are not returned:

'abracadabra'.split(/ab/) # => ["", "racad", "ra"]
'aaabcdaaa'.split(/a/)   => ["", "", "", "bcd"]
'aaabcdaaa'.split(//)    => ["a", "a", "a", "b", "c", "d", "a", "a", "a"]
'1 + 1 == 2'.split(/\W+/) # => ["1", "1", "2"]

If the Regexp contains groups, their matches are also included in the returned array:

'1:2:3'.split(/(:)()()/, 2) # => ["1", ":", "", "", "2:3"]

As seen above, if limit is nil, trailing empty substrings are not returned; the same is true if limit is zero:

'aaabcdaaa'.split('a')   => ["", "", "", "bcd"]
'aaabcdaaa'.split('a', 0) # => ["", "", "", "bcd"]

If limit is positive integer n, no more than n - 1- splits occur, so that at most n substrings are returned, and trailing empty substrings are included:

'aaabcdaaa'.split('a', 1) # => ["aaabcdaaa"]
'aaabcdaaa'.split('a', 2) # => ["", "aabcdaaa"]
'aaabcdaaa'.split('a', 5) # => ["", "", "", "bcd", "aa"]
'aaabcdaaa'.split('a', 7) # => ["", "", "", "bcd", "", "", ""]
'aaabcdaaa'.split('a', 8) # => ["", "", "", "bcd", "", "", ""]

Note that if field_sep is a Regexp containing groups, their matches are in the returned array, but do not count toward the limit.

If limit is negative, it behaves the same as if limit was nil, meaning that there is no limit, and trailing empty substrings are included:

'aaabcdaaa'.split('a', -1) # => ["", "", "", "bcd", "", "", ""]

If a block is given, it is called with each substring:

'abc def ghi'.split(' ') {|substring| p substring }

Output:

"abc"
"def"
"ghi"

squeeze(*selectors) → new_string

string.c View on GitHub

          
            static VALUE
rb_str_squeeze(int argc, VALUE *argv, VALUE str)
{
    str = str_duplicate(rb_cString, str);
    rb_str_squeeze_bang(argc, argv, str);
    return str;
}

Returns a copy of self with characters specified by selectors “squeezed” (see Multiple Character Selectors):

“Squeezed” means that each multiple-character run of a selected character is squeezed down to a single character; with no arguments given, squeezes all characters:

"yellow moon".squeeze                  #=> "yelow mon"
"  now   is  the".squeeze(" ")         #=> " now is the"
"putters shoot balls".squeeze("m-z")   #=> "puters shot balls"

squeeze!(*selectors) → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_squeeze_bang(int argc, VALUE *argv, VALUE str)
{
    char squeez[TR_TABLE_SIZE];
    rb_encoding *enc = 0;
    VALUE del = 0, nodel = 0;
    unsigned char *s, *send, *t;
    int i, modify = 0;
    int ascompat, singlebyte = single_byte_optimizable(str);
    unsigned int save;

    if (argc == 0) {
        enc = STR_ENC_GET(str);
    }
    else {
        for (i=0; i<argc; i++) {
            VALUE s = argv[i];

            StringValue(s);
            enc = rb_enc_check(str, s);
            if (singlebyte && !single_byte_optimizable(s))
                singlebyte = 0;
            tr_setup_table(s, squeez, i==0, &del, &nodel, enc);
        }
    }

    str_modify_keep_cr(str);
    s = t = (unsigned char *)RSTRING_PTR(str);
    if (!s || RSTRING_LEN(str) == 0) return Qnil;
    send = (unsigned char *)RSTRING_END(str);
    save = -1;
    ascompat = rb_enc_asciicompat(enc);

    if (singlebyte) {
        while (s < send) {
            unsigned int c = *s++;
            if (c != save || (argc > 0 && !squeez[c])) {
                *t++ = save = c;
            }
        }
    }
    else {
        while (s < send) {
            unsigned int c;
            int clen;

            if (ascompat && (c = *s) < 0x80) {
                if (c != save || (argc > 0 && !squeez[c])) {
                    *t++ = save = c;
                }
                s++;
            }
            else {
                c = rb_enc_codepoint_len((char *)s, (char *)send, &clen, enc);

                if (c != save || (argc > 0 && !tr_find(c, squeez, del, nodel))) {
                    if (t != s) rb_enc_mbcput(c, t, enc);
                    save = c;
                    t += clen;
                }
                s += clen;
            }
        }
    }

    TERM_FILL((char *)t, TERM_LEN(str));
    if ((char *)t - RSTRING_PTR(str) != RSTRING_LEN(str)) {
        STR_SET_LEN(str, (char *)t - RSTRING_PTR(str));
        modify = 1;
    }

    if (modify) return str;
    return Qnil;
}

Like String#squeeze, but modifies self in place. Returns self if any changes were made, nil otherwise.

start_with?(*string_or_regexp) → true or false

string.c View on GitHub

          
            static VALUE
rb_str_start_with(int argc, VALUE *argv, VALUE str)
{
    int i;

    for (i=0; i<argc; i++) {
        VALUE tmp = argv[i];
        if (RB_TYPE_P(tmp, T_REGEXP)) {
            if (rb_reg_start_with_p(tmp, str))
                return Qtrue;
        }
        else {
            const char *p, *s, *e;
            long slen, tlen;
            rb_encoding *enc;

            StringValue(tmp);
            enc = rb_enc_check(str, tmp);
            if ((tlen = RSTRING_LEN(tmp)) == 0) return Qtrue;
            if ((slen = RSTRING_LEN(str)) < tlen) continue;
            p = RSTRING_PTR(str);
            e = p + slen;
            s = p + tlen;
            if (!at_char_right_boundary(p, s, e, enc))
                continue;
            if (memcmp(p, RSTRING_PTR(tmp), tlen) == 0)
                return Qtrue;
        }
    }
    return Qfalse;
}

Returns whether self starts with any of the given string_or_regexp.

Matches patterns against the beginning of self. For each given string_or_regexp, the pattern is:

string_or_regexp itself, if it is a Regexp.
Regexp.quote(string_or_regexp), if string_or_regexp is a string.

Returns true if any pattern matches the beginning, false otherwise:

'hello'.start_with?('hell')               # => true
'hello'.start_with?(/H/i)                 # => true
'hello'.start_with?('heaven', 'hell')     # => true
'hello'.start_with?('heaven', 'paradise') # => false
'тест'.start_with?('т')                   # => true
'こんにちは'.start_with?('こ')              # => true

Related: String#end_with?.

strip → new_string

string.c View on GitHub

          
            static VALUE
rb_str_strip(VALUE str)
{
    char *start;
    long olen, loffset, roffset;
    rb_encoding *enc = STR_ENC_GET(str);

    RSTRING_GETMEM(str, start, olen);
    loffset = lstrip_offset(str, start, start+olen, enc);
    roffset = rstrip_offset(str, start+loffset, start+olen, enc);

    if (loffset <= 0 && roffset <= 0) return str_duplicate(rb_cString, str);
    return rb_str_subseq(str, loffset, olen-loffset-roffset);
}

Returns a copy of the receiver with leading and trailing whitespace removed; see Whitespace in Strings:

whitespace = "\x00\t\n\v\f\r "
s = whitespace + 'abc' + whitespace
s       # => "\u0000\t\n\v\f\r abc\u0000\t\n\v\f\r "
s.strip # => "abc"

strip! → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_strip_bang(VALUE str)
{
    char *start;
    long olen, loffset, roffset;
    rb_encoding *enc;

    str_modify_keep_cr(str);
    enc = STR_ENC_GET(str);
    RSTRING_GETMEM(str, start, olen);
    loffset = lstrip_offset(str, start, start+olen, enc);
    roffset = rstrip_offset(str, start+loffset, start+olen, enc);

    if (loffset > 0 || roffset > 0) {
        long len = olen-roffset;
        if (loffset > 0) {
            len -= loffset;
            memmove(start, start + loffset, len);
        }
        STR_SET_LEN(str, len);
        TERM_FILL(start+len, rb_enc_mbminlen(enc));
        return str;
    }
    return Qnil;
}

Like String#strip, except that any modifications are made in self; returns self if any modification are made, nil otherwise.

sub(pattern, replacement) → new_string

sub(pattern) {|match| ... } → new_string

string.c View on GitHub

          
            static VALUE
rb_str_sub(int argc, VALUE *argv, VALUE str)
{
    str = str_duplicate(rb_cString, str);
    rb_str_sub_bang(argc, argv, str);
    return str;
}

Returns a copy of self with only the first occurrence (not all occurrences) of the given pattern replaced.

See Substitution Methods.

sub!(pattern, replacement) → self or nil

sub!(pattern) {|match| ... } → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_sub_bang(int argc, VALUE *argv, VALUE str)
{
    VALUE pat, repl, hash = Qnil;
    int iter = 0;
    long plen;
    int min_arity = rb_block_given_p() ? 1 : 2;
    long beg;

    rb_check_arity(argc, min_arity, 2);
    if (argc == 1) {
        iter = 1;
    }
    else {
        repl = argv[1];
        hash = rb_check_hash_type(argv[1]);
        if (NIL_P(hash)) {
            StringValue(repl);
        }
    }

    pat = get_pat_quoted(argv[0], 1);

    str_modifiable(str);
    beg = rb_pat_search(pat, str, 0, 1);
    if (beg >= 0) {
        rb_encoding *enc;
        int cr = ENC_CODERANGE(str);
        long beg0, end0;
        VALUE match, match0 = Qnil;
        struct re_registers *regs;
        char *p, *rp;
        long len, rlen;

        match = rb_backref_get();
        regs = RMATCH_REGS(match);
        if (RB_TYPE_P(pat, T_STRING)) {
            beg0 = beg;
            end0 = beg0 + RSTRING_LEN(pat);
            match0 = pat;
        }
        else {
            beg0 = BEG(0);
            end0 = END(0);
            if (iter) match0 = rb_reg_nth_match(0, match);
        }

        if (iter || !NIL_P(hash)) {
            p = RSTRING_PTR(str); len = RSTRING_LEN(str);

            if (iter) {
                repl = rb_obj_as_string(rb_yield(match0));
            }
            else {
                repl = rb_hash_aref(hash, rb_str_subseq(str, beg0, end0 - beg0));
                repl = rb_obj_as_string(repl);
            }
            str_mod_check(str, p, len);
            rb_check_frozen(str);
        }
        else {
            repl = rb_reg_regsub(repl, str, regs, RB_TYPE_P(pat, T_STRING) ? Qnil : pat);
        }

        enc = rb_enc_compatible(str, repl);
        if (!enc) {
            rb_encoding *str_enc = STR_ENC_GET(str);
            p = RSTRING_PTR(str); len = RSTRING_LEN(str);
            if (coderange_scan(p, beg0, str_enc) != ENC_CODERANGE_7BIT ||
                coderange_scan(p+end0, len-end0, str_enc) != ENC_CODERANGE_7BIT) {
                rb_raise(rb_eEncCompatError, "incompatible character encodings: %s and %s",
                         rb_enc_inspect_name(str_enc),
                         rb_enc_inspect_name(STR_ENC_GET(repl)));
            }
            enc = STR_ENC_GET(repl);
        }
        rb_str_modify(str);
        rb_enc_associate(str, enc);
        if (ENC_CODERANGE_UNKNOWN < cr && cr < ENC_CODERANGE_BROKEN) {
            int cr2 = ENC_CODERANGE(repl);
            if (cr2 == ENC_CODERANGE_BROKEN ||
                (cr == ENC_CODERANGE_VALID && cr2 == ENC_CODERANGE_7BIT))
                cr = ENC_CODERANGE_UNKNOWN;
            else
                cr = cr2;
        }
        plen = end0 - beg0;
        rlen = RSTRING_LEN(repl);
        len = RSTRING_LEN(str);
        if (rlen > plen) {
            RESIZE_CAPA(str, len + rlen - plen);
        }
        p = RSTRING_PTR(str);
        if (rlen != plen) {
            memmove(p + beg0 + rlen, p + beg0 + plen, len - beg0 - plen);
        }
        rp = RSTRING_PTR(repl);
        memmove(p + beg0, rp, rlen);
        len += rlen - plen;
        STR_SET_LEN(str, len);
        TERM_FILL(&RSTRING_PTR(str)[len], TERM_LEN(str));
        ENC_CODERANGE_SET(str, cr);

        RB_GC_GUARD(match);

        return str;
    }
    return Qnil;
}

Returns self with only the first occurrence (not all occurrences) of the given pattern replaced.

See Substitution Methods.

succ → new_str

string.c View on GitHub

          
            VALUE
rb_str_succ(VALUE orig)
{
    VALUE str;
    str = rb_str_new(RSTRING_PTR(orig), RSTRING_LEN(orig));
    rb_enc_cr_str_copy_for_substr(str, orig);
    return str_succ(str);
}

Returns the successor to self. The successor is calculated by incrementing characters.

The first character to be incremented is the rightmost alphanumeric: or, if no alphanumerics, the rightmost character:

'THX1138'.succ # => "THX1139"
'<<koala>>'.succ # => "<<koalb>>"
'***'.succ # => '**+'

The successor to a digit is another digit, “carrying” to the next-left character for a “rollover” from 9 to 0, and prepending another digit if necessary:

'00'.succ # => "01"
'09'.succ # => "10"
'99'.succ # => "100"

The successor to a letter is another letter of the same case, carrying to the next-left character for a rollover, and prepending another same-case letter if necessary:

'aa'.succ # => "ab"
'az'.succ # => "ba"
'zz'.succ # => "aaa"
'AA'.succ # => "AB"
'AZ'.succ # => "BA"
'ZZ'.succ # => "AAA"

The successor to a non-alphanumeric character is the next character in the underlying character set’s collating sequence, carrying to the next-left character for a rollover, and prepending another character if necessary:

s = 0.chr * 3
s # => "\x00\x00\x00"
s.succ # => "\x00\x00\x01"
s = 255.chr * 3
s # => "\xFF\xFF\xFF"
s.succ # => "\x01\x00\x00\x00"

Carrying can occur between and among mixtures of alphanumeric characters:

s = 'zz99zz99'
s.succ # => "aaa00aa00"
s = '99zz99zz'
s.succ # => "100aa00aa"

The successor to an empty String is a new empty String:

''.succ # => ""

succ! → self

string.c View on GitHub

          
            static VALUE
rb_str_succ_bang(VALUE str)
{
    rb_str_modify(str);
    str_succ(str);
    return str;
}

Equivalent to String#succ, but modifies self in place; returns self.

sum(n = 16) → integer

string.c View on GitHub

          
            static VALUE
rb_str_sum(int argc, VALUE *argv, VALUE str)
{
    int bits = 16;
    char *ptr, *p, *pend;
    long len;
    VALUE sum = INT2FIX(0);
    unsigned long sum0 = 0;

    if (rb_check_arity(argc, 0, 1) && (bits = NUM2INT(argv[0])) < 0) {
        bits = 0;
    }
    ptr = p = RSTRING_PTR(str);
    len = RSTRING_LEN(str);
    pend = p + len;

    while (p < pend) {
        if (FIXNUM_MAX - UCHAR_MAX < sum0) {
            sum = rb_funcall(sum, '+', 1, LONG2FIX(sum0));
            str_mod_check(str, ptr, len);
            sum0 = 0;
        }
        sum0 += (unsigned char)*p;
        p++;
    }

    if (bits == 0) {
        if (sum0) {
            sum = rb_funcall(sum, '+', 1, LONG2FIX(sum0));
        }
    }
    else {
        if (sum == INT2FIX(0)) {
            if (bits < (int)sizeof(long)*CHAR_BIT) {
                sum0 &= (((unsigned long)1)<<bits)-1;
            }
            sum = LONG2FIX(sum0);
        }
        else {
            VALUE mod;

            if (sum0) {
                sum = rb_funcall(sum, '+', 1, LONG2FIX(sum0));
            }

            mod = rb_funcall(INT2FIX(1), idLTLT, 1, INT2FIX(bits));
            mod = rb_funcall(mod, '-', 1, INT2FIX(1));
            sum = rb_funcall(sum, '&', 1, mod);
        }
    }
    return sum;
}

Returns a basic n-bit checksum of the characters in self; the checksum is the sum of the binary value of each byte in self, modulo 2**n - 1:

'hello'.sum     # => 532
'hello'.sum(4)  # => 4
'hello'.sum(64) # => 532
'тест'.sum      # => 1405
'こんにちは'.sum  # => 2582

This is not a particularly strong checksum.

swapcase(*options) → string

string.c View on GitHub

          
            static VALUE
rb_str_swapcase(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_UPCASE | ONIGENC_CASE_DOWNCASE;
    VALUE ret;

    flags = check_case_options(argc, argv, flags);
    enc = str_true_enc(str);
    if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return str_duplicate(rb_cString, str);
    if (flags&ONIGENC_CASE_ASCII_ONLY) {
        ret = rb_str_new(0, RSTRING_LEN(str));
        rb_str_ascii_casemap(str, ret, &flags, enc);
    }
    else {
        ret = rb_str_casemap(str, &flags, enc);
    }
    return ret;
}

Returns a string containing the characters in self, with cases reversed; each uppercase character is downcased; each lowercase character is upcased:

s = 'Hello World!' # => "Hello World!"
s.swapcase         # => "hELLO wORLD!"

The casing may be affected by the given options; see Case Mapping.

Related: String#swapcase!.

swapcase!(*options) → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_swapcase_bang(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_UPCASE | ONIGENC_CASE_DOWNCASE;

    flags = check_case_options(argc, argv, flags);
    str_modify_keep_cr(str);
    enc = str_true_enc(str);
    if (flags&ONIGENC_CASE_ASCII_ONLY)
        rb_str_ascii_casemap(str, str, &flags, enc);
    else
        str_shared_replace(str, rb_str_casemap(str, &flags, enc));

    if (ONIGENC_CASE_MODIFIED&flags) return str;
    return Qnil;
}

Upcases each lowercase character in self; downcases uppercase character; returns self if any changes were made, nil otherwise:

s = 'Hello World!' # => "Hello World!"
s.swapcase!        # => "hELLO wORLD!"
s                  # => "hELLO wORLD!"
''.swapcase!       # => nil

The casing may be affected by the given options; see Case Mapping.

Related: String#swapcase.

to_c → complex

complex.c View on GitHub

          
            static VALUE
string_to_c(VALUE self)
{
    VALUE num;

    rb_must_asciicompat(self);

    (void)parse_comp(rb_str_fill_terminator(self, 1), FALSE, &num);

    return num;
}

Returns self interpreted as a Complex object; leading whitespace and trailing garbage are ignored:

'9'.to_c                 # => (9+0i)
'2.5'.to_c               # => (2.5+0i)
'2.5/1'.to_c             # => ((5/2)+0i)
'-3/2'.to_c              # => ((-3/2)+0i)
'-i'.to_c                # => (0-1i)
'45i'.to_c               # => (0+45i)
'3-4i'.to_c              # => (3-4i)
'-4e2-4e-2i'.to_c        # => (-400.0-0.04i)
'-0.0-0.0i'.to_c         # => (-0.0-0.0i)
'1/2+3/4i'.to_c          # => ((1/2)+(3/4)*i)
'1.0@0'.to_c             # => (1+0.0i)
"1.0@#{Math::PI/2}".to_c # => (0.0+1i)
"1.0@#{Math::PI}".to_c   # => (-1+0.0i)

Returns Complex zero if the string cannot be converted:

'ruby'.to_c        # => (0+0i)

See Kernel#Complex.

to_f → float

string.c View on GitHub

          
            static VALUE
rb_str_to_f(VALUE str)
{
    return DBL2NUM(rb_str_to_dbl(str, FALSE));
}

Returns the result of interpreting leading characters in self as a Float:

'3.14159'.to_f  # => 3.14159
'1.234e-2'.to_f # => 0.01234

Characters past a leading valid number (in the given base) are ignored:

'3.14 (pi to two places)'.to_f # => 3.14

Returns zero if there is no leading valid number:

'abcdef'.to_f # => 0.0

to_i(base = 10) → integer

string.c View on GitHub

          
            static VALUE
rb_str_to_i(int argc, VALUE *argv, VALUE str)
{
    int base = 10;

    if (rb_check_arity(argc, 0, 1) && (base = NUM2INT(argv[0])) < 0) {
        rb_raise(rb_eArgError, "invalid radix %d", base);
    }
    return rb_str_to_inum(str, base, FALSE);
}

Returns the result of interpreting leading characters in self as an integer in the given base (which must be in (0, 2..36)):

'123456'.to_i     # => 123456
'123def'.to_i(16) # => 1195503

With base zero, string object may contain leading characters to specify the actual base:

'123def'.to_i(0)   # => 123
'0123def'.to_i(0)  # => 83
'0b123def'.to_i(0) # => 1
'0o123def'.to_i(0) # => 83
'0d123def'.to_i(0) # => 123
'0x123def'.to_i(0) # => 1195503

Characters past a leading valid number (in the given base) are ignored:

'12.345'.to_i   # => 12
'12345'.to_i(2) # => 1

Returns zero if there is no leading valid number:

'abcdef'.to_i # => 0
'2'.to_i(2)   # => 0

str.to_r → rational

rational.c View on GitHub

          
            static VALUE
string_to_r(VALUE self)
{
    VALUE num;

    rb_must_asciicompat(self);

    num = parse_rat(RSTRING_PTR(self), RSTRING_END(self), 0, TRUE);

    if (RB_FLOAT_TYPE_P(num) && !FLOAT_ZERO_P(num))
        rb_raise(rb_eFloatDomainError, "Infinity");
    return num;
}

Returns the result of interpreting leading characters in str as a rational. Leading whitespace and extraneous characters past the end of a valid number are ignored. Digit sequences can be separated by an underscore. If there is not a valid number at the start of str, zero is returned. This method never raises an exception.

'  2  '.to_r       #=> (2/1)
'300/2'.to_r       #=> (150/1)
'-9.2'.to_r        #=> (-46/5)
'-9.2e2'.to_r      #=> (-920/1)
'1_234_567'.to_r   #=> (1234567/1)
'21 June 09'.to_r  #=> (21/1)
'21/06/09'.to_r    #=> (7/2)
'BWV 1079'.to_r    #=> (0/1)

NOTE: “0.3”.to_r isn’t the same as 0.3.to_r. The former is equivalent to “3/10”.to_r, but the latter isn’t so.

"0.3".to_r == 3/10r  #=> true
0.3.to_r   == 3/10r  #=> false

to_s → self or string

string.c View on GitHub

          
            static VALUE
rb_str_to_s(VALUE str)
{
    if (rb_obj_class(str) != rb_cString) {
        return str_duplicate(rb_cString, str);
    }
    return str;
}

Returns self if self is a String, or self converted to a String if self is a subclass of String.

to_str

string.c View on GitHub

An alias for to_s

str.to_sym → symbol

string.c View on GitHub

An alias for intern

tr(selector, replacements) → new_string

string.c View on GitHub

          
            static VALUE
rb_str_tr(VALUE str, VALUE src, VALUE repl)
{
    str = str_duplicate(rb_cString, str);
    tr_trans(str, src, repl, 0);
    return str;
}

Returns a copy of self with each character specified by string selector translated to the corresponding character in string replacements. The correspondence is positional:

Each occurrence of the first character specified by selector is translated to the first character in replacements.
Each occurrence of the second character specified by selector is translated to the second character in replacements.
And so on.

Example:

'hello'.tr('el', 'ip') #=> "hippo"

If replacements is shorter than selector, it is implicitly padded with its own last character:

'hello'.tr('aeiou', '-')   # => "h-ll-"
'hello'.tr('aeiou', 'AA-') # => "hAll-"

Arguments selector and replacements must be valid character selectors (see Character Selectors), and may use any of its valid forms, including negation, ranges, and escaping:

# Negation.
'hello'.tr('^aeiou', '-') # => "-e--o"
# Ranges.
'ibm'.tr('b-z', 'a-z') # => "hal"
# Escapes.
'hel^lo'.tr('\^aeiou', '-')     # => "h-l-l-"    # Escaped leading caret.
'i-b-m'.tr('b\-z', 'a-z')       # => "ibabm"     # Escaped embedded hyphen.
'foo\\bar'.tr('ab\\', 'XYZ')    # => "fooZYXr"   # Escaped backslash.

tr!(selector, replacements) → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_tr_bang(VALUE str, VALUE src, VALUE repl)
{
    return tr_trans(str, src, repl, 0);
}

Like String#tr, but modifies self in place. Returns self if any changes were made, nil otherwise.

tr_s(selector, replacements) → string

string.c View on GitHub

          
            static VALUE
rb_str_tr_s(VALUE str, VALUE src, VALUE repl)
{
    str = str_duplicate(rb_cString, str);
    tr_trans(str, src, repl, 1);
    return str;
}

Like String#tr, but also squeezes the modified portions of the translated string; returns a new string (translated and squeezed).

'hello'.tr_s('l', 'r')   #=> "hero"
'hello'.tr_s('el', '-')  #=> "h-o"
'hello'.tr_s('el', 'hx') #=> "hhxo"

Related: String#squeeze.

tr_s!(selector, replacements) → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_tr_s_bang(VALUE str, VALUE src, VALUE repl)
{
    return tr_trans(str, src, repl, 1);
}

Like String#tr_s, but modifies self in place. Returns self if any changes were made, nil otherwise.

Related: String#squeeze!.

undump → string

string.c View on GitHub

          
            static VALUE
str_undump(VALUE str)
{
    const char *s = RSTRING_PTR(str);
    const char *s_end = RSTRING_END(str);
    rb_encoding *enc = rb_enc_get(str);
    VALUE undumped = rb_enc_str_new(s, 0L, enc);
    bool utf8 = false;
    bool binary = false;
    int w;

    rb_must_asciicompat(str);
    if (rb_str_is_ascii_only_p(str) == Qfalse) {
        rb_raise(rb_eRuntimeError, "non-ASCII character detected");
    }
    if (!str_null_check(str, &w)) {
        rb_raise(rb_eRuntimeError, "string contains null byte");
    }
    if (RSTRING_LEN(str) < 2) goto invalid_format;
    if (*s != '"') goto invalid_format;

    /* strip '"' at the start */
    s++;

    for (;;) {
        if (s >= s_end) {
            rb_raise(rb_eRuntimeError, "unterminated dumped string");
        }

        if (*s == '"') {
            /* epilogue */
            s++;
            if (s == s_end) {
                /* ascii compatible dumped string */
                break;
            }
            else {
                static const char force_encoding_suffix[] = ".force_encoding(\""; /* "\")" */
                static const char dup_suffix[] = ".dup";
                const char *encname;
                int encidx;
                ptrdiff_t size;

                /* check separately for strings dumped by older versions */
                size = sizeof(dup_suffix) - 1;
                if (s_end - s > size && memcmp(s, dup_suffix, size) == 0) s += size;

                size = sizeof(force_encoding_suffix) - 1;
                if (s_end - s <= size) goto invalid_format;
                if (memcmp(s, force_encoding_suffix, size) != 0) goto invalid_format;
                s += size;

                if (utf8) {
                    rb_raise(rb_eRuntimeError, "dumped string contained Unicode escape but used force_encoding");
                }

                encname = s;
                s = memchr(s, '"', s_end-s);
                size = s - encname;
                if (!s) goto invalid_format;
                if (s_end - s != 2) goto invalid_format;
                if (s[0] != '"' || s[1] != ')') goto invalid_format;

                encidx = rb_enc_find_index2(encname, (long)size);
                if (encidx < 0) {
                    rb_raise(rb_eRuntimeError, "dumped string has unknown encoding name");
                }
                rb_enc_associate_index(undumped, encidx);
            }
            break;
        }

        if (*s == '\\') {
            s++;
            if (s >= s_end) {
                rb_raise(rb_eRuntimeError, "invalid escape");
            }
            undump_after_backslash(undumped, &s, s_end, &enc, &utf8, &binary);
        }
        else {
            rb_str_cat(undumped, s++, 1);
        }
    }

    RB_GC_GUARD(str);

    return undumped;
invalid_format:
    rb_raise(rb_eRuntimeError, "invalid dumped string; not wrapped with '\"' nor '\"...\".force_encoding(\"...\")' form");
}

Returns an unescaped version of self:

s_orig = "\f\x00\xff\\\""    # => "\f\u0000\xFF\\\""
s_dumped = s_orig.dump       # => "\"\\f\\x00\\xFF\\\\\\\"\""
s_undumped = s_dumped.undump # => "\f\u0000\xFF\\\""
s_undumped == s_orig         # => true

Related: String#dump (inverse of String#undump).

unicode_normalize(form = :nfc) → string

string.c View on GitHub

          
            static VALUE
rb_str_unicode_normalize(int argc, VALUE *argv, VALUE str)
{
    return unicode_normalize_common(argc, argv, str, id_normalize);
}

Returns a copy of self with Unicode normalization applied.

Argument form must be one of the following symbols (see Unicode normalization forms):

:nfc: Canonical decomposition, followed by canonical composition.
:nfd: Canonical decomposition.
:nfkc: Compatibility decomposition, followed by canonical composition.
:nfkd: Compatibility decomposition.

The encoding of self must be one of:

Encoding::UTF_8
Encoding::UTF_16BE
Encoding::UTF_16LE
Encoding::UTF_32BE
Encoding::UTF_32LE
Encoding::GB18030
Encoding::UCS_2BE
Encoding::UCS_4BE

Examples:

"a\u0300".unicode_normalize      # => "a"
"\u00E0".unicode_normalize(:nfd) # => "a "

unicode_normalize!(form = :nfc) → self

string.c View on GitHub

          
            static VALUE
rb_str_unicode_normalize_bang(int argc, VALUE *argv, VALUE str)
{
    return rb_str_replace(str, unicode_normalize_common(argc, argv, str, id_normalize));
}

Like String#unicode_normalize, except that the normalization is performed on self.

Related String#unicode_normalized?.

unicode_normalized?(form = :nfc) → true or false

string.c View on GitHub

          
            static VALUE
rb_str_unicode_normalized_p(int argc, VALUE *argv, VALUE str)
{
    return unicode_normalize_common(argc, argv, str, id_normalized_p);
}

Returns true if self is in the given form of Unicode normalization, false otherwise. The form must be one of :nfc, :nfd, :nfkc, or :nfkd.

Examples:

"a\u0300".unicode_normalized?       # => false
"a\u0300".unicode_normalized?(:nfd) # => true
"\u00E0".unicode_normalized?        # => true
"\u00E0".unicode_normalized?(:nfd)  # => false

Raises an exception if self is not in a Unicode encoding:

s = "\xE0".force_encoding('ISO-8859-1')
s.unicode_normalized? # Raises Encoding::CompatibilityError.

unpack(template, offset: 0) → array

pack.rb View on GitHub

          
            # File tmp/rubies/ruby-3.4.0-preview1/pack.rb, line 19
def unpack(fmt, offset: 0)
  Primitive.attr! :use_block
  Primitive.pack_unpack(fmt, offset)
end

Extracts data from self, forming objects that become the elements of a new array; returns that array. See Packed Data.

unpack1(template, offset: 0) → object

pack.rb View on GitHub

          
            # File tmp/rubies/ruby-3.4.0-preview1/pack.rb, line 29
def unpack1(fmt, offset: 0)
  Primitive.pack_unpack1(fmt, offset)
end

Like String#unpack, but unpacks and returns only the first extracted object. See Packed Data.

upcase(*options) → string

string.c View on GitHub

          
            static VALUE
rb_str_upcase(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_UPCASE;
    VALUE ret;

    flags = check_case_options(argc, argv, flags);
    enc = str_true_enc(str);
    if (case_option_single_p(flags, enc, str)) {
        ret = rb_str_new(RSTRING_PTR(str), RSTRING_LEN(str));
        str_enc_copy_direct(ret, str);
        upcase_single(ret);
    }
    else if (flags&ONIGENC_CASE_ASCII_ONLY) {
        ret = rb_str_new(0, RSTRING_LEN(str));
        rb_str_ascii_casemap(str, ret, &flags, enc);
    }
    else {
        ret = rb_str_casemap(str, &flags, enc);
    }

    return ret;
}

Returns a string containing the upcased characters in self:

s = 'Hello World!' # => "Hello World!"
s.upcase           # => "HELLO WORLD!"

The casing may be affected by the given options; see Case Mapping.

upcase!(*options) → self or nil

string.c View on GitHub

          
            static VALUE
rb_str_upcase_bang(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    OnigCaseFoldType flags = ONIGENC_CASE_UPCASE;

    flags = check_case_options(argc, argv, flags);
    str_modify_keep_cr(str);
    enc = str_true_enc(str);
    if (case_option_single_p(flags, enc, str)) {
        if (upcase_single(str))
            flags |= ONIGENC_CASE_MODIFIED;
    }
    else if (flags&ONIGENC_CASE_ASCII_ONLY)
        rb_str_ascii_casemap(str, str, &flags, enc);
    else
        str_shared_replace(str, rb_str_casemap(str, &flags, enc));

    if (ONIGENC_CASE_MODIFIED&flags) return str;
    return Qnil;
}

Upcases the characters in self; returns self if any changes were made, nil otherwise:

s = 'Hello World!' # => "Hello World!"
s.upcase!          # => "HELLO WORLD!"
s                  # => "HELLO WORLD!"
s.upcase!          # => nil

The casing may be affected by the given options; see Case Mapping.

upto(other_string, exclusive = false) {|string| ... } → self

upto(other_string, exclusive = false) → new_enumerator

string.c View on GitHub

          
            static VALUE
rb_str_upto(int argc, VALUE *argv, VALUE beg)
{
    VALUE end, exclusive;

    rb_scan_args(argc, argv, "11", &end, &exclusive);
    RETURN_ENUMERATOR(beg, argc, argv);
    return rb_str_upto_each(beg, end, RTEST(exclusive), str_upto_i, Qnil);
}

With a block given, calls the block with each String value returned by successive calls to String#succ; the first value is self, the next is self.succ, and so on; the sequence terminates when value other_string is reached; returns self:

'a8'.upto('b6') {|s| print s, ' ' } # => "a8"

Output:

a8 a9 b0 b1 b2 b3 b4 b5 b6

If argument exclusive is given as a truthy object, the last value is omitted:

'a8'.upto('b6', true) {|s| print s, ' ' } # => "a8"

Output:

a8 a9 b0 b1 b2 b3 b4 b5

If other_string would not be reached, does not call the block:

'25'.upto('5') {|s| fail s }
'aa'.upto('a') {|s| fail s }

With no block given, returns a new Enumerator:

'a8'.upto('b6') # => #<Enumerator: "a8":upto("b6")>

valid_encoding? → true or false

string.c View on GitHub

          
            static VALUE
rb_str_valid_encoding_p(VALUE str)
{
    int cr = rb_enc_str_coderange(str);

    return RBOOL(cr != ENC_CODERANGE_BROKEN);
}

Returns true if self is encoded correctly, false otherwise:

"\xc2\xa1".force_encoding("UTF-8").valid_encoding? # => true
"\xc2".force_encoding("UTF-8").valid_encoding?     # => false
"\x80".force_encoding("UTF-8").valid_encoding?     # => false

String

Substitution Methods

Whitespace in Strings

String Slices

What’s Here

Methods for Creating a String

Methods for a Frozen/Unfrozen String

Methods for Querying

Methods for Comparing

Methods for Modifying a String

Methods for Converting to New String

Methods for Converting to Non-String

Methods for Iterating

String.new(string = '', **opts) → new_string

String.try_convert(object) → object, new_string, or nil

string % object → new_string

string * integer → new_string

string + other_string → new_string

+string → new_string or self

-string → frozen_string

string << object → string

string <=> other_string → -1, 0, 1, or nil

string == object → true or false

string === object → true or false

string =~ regexp → integer or nil

string =~ object → integer or nil

string[index] → new_string or nil

string[start, length] → new_string or nil

string[range] → new_string or nil

string[regexp, capture = 0] → new_string or nil

string[substring] → new_string or nil

string[index] = new_string

string[start, length] = new_string

string[range] = new_string

string[regexp, capture = 0] = new_string

string[substring] = new_string

ascii_only? → true or false

b → string

byteindex(substring, offset = 0) → integer or nil

byteindex(regexp, offset = 0) → integer or nil

byterindex(substring, offset = self.bytesize) → integer or nil

byterindex(regexp, offset = self.bytesize) → integer or nil

bytes → array_of_bytes

bytesize → integer

byteslice(index, length = 1) → string or nil

byteslice(range) → string or nil

bytesplice(index, length, str) → string

bytesplice(index, length, str, str_index, str_length) → string

bytesplice(range, str) → string

bytesplice(range, str, str_range) → string

capitalize(*options) → string

capitalize!(*options) → self or nil

casecmp(other_string) → -1, 0, 1, or nil

casecmp?(other_string) → true, false, or nil

center(size, pad_string = ' ') → new_string

chars → array_of_characters

chomp(line_sep = $/) → new_string

chomp!(line_sep = $/) → self or nil

chop → new_string

chop! → self or nil

chr → string

clear → self

codepoints → array_of_integers

concat(*objects) → string

count(*selectors) → integer

crypt(salt_str) → new_string

-string → frozen_string

dedup → frozen_string

delete(*selectors) → new_string

delete!(*selectors) → self or nil

delete_prefix(prefix) → new_string

delete_prefix!(prefix) → self or nil

delete_suffix(suffix) → new_string

delete_suffix!(suffix) → self or nil

downcase(*options) → string

downcase!(*options) → self or nil

dump → string

each_byte {|byte| ... } → self

each_byte → enumerator

each_char {|c| ... } → self

`String` Slices

Methods for Creating a `String`

Methods for a Frozen/Unfrozen `String`

Methods for Modifying a `String`

Methods for Converting to New `String`

Methods for Converting to Non-`String`