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
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
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"
Related: String#ljust, String#rjust.
Returns a copy of self with only the first occurrence (not all occurrences) of the given pattern replaced.
See Substitution Methods.
Related: String#sub!, String#gsub, String#gsub!.
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.
Related: String#sub, String#sub!, String#gsub!.
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.
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"
Replaces the first occurrence (not all occurrences) of the given pattern on self; returns self if a replacement occurred, nil otherwise.
See Substitution Methods.
Related: String#sub, String#gsub, String#gsub!.
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.
Related: String#sub, String#gsub, String#sub!.
Like String#chop, but modifies self in place; returns nil if self is empty, self otherwise.
Related: String#chomp!.
Like String#chomp, but modifies self in place; returns nil if no modification made, self otherwise.
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"
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"
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
Like String#delete, but modifies self in place. Returns self if any changes were made, nil otherwise.
Like String#squeeze, but modifies self in place. Returns self if any changes were made, nil otherwise.
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.
Returns the substring of self specified by the arguments. See examples at String Slices.
Related: see Converting to New String.
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"
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", "", ""]
Related: String#rpartition, String#split.
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"]
Related: String#partition, String#split.
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]
Related: see Converting to New String.
Returns a frozen string equal to self.
The returned string is self if and only if all of the following are true:
self is already frozen.
self is an instance of String (rather than of a subclass of String)
self has no instance variables set on it.
Otherwise, the returned string is a frozen copy of self.
Returning self, when possible, saves duplicating self; see Data deduplication.
It may also save duplicating other, already-existing, strings:
s0 = 'foo' s1 = 'foo' s0.object_id == s1.object_id # => false (-s0).object_id == (-s1).object_id # => true
Note that method -@ is convenient for defining a constant:
FileName = -'config/database.yml'
While its alias dedup is better suited for chaining:
'foo'.dedup.gsub!('o')
Related: see Freezing/Unfreezing.
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.
Like encode, but applies encoding changes to self; returns self.