Returns the integer hash value for self. The value is based on the length, content and encoding of self.
Related: Object#hash.
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?.
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.
Returns a new String containing other_string concatenated to self:
"Hello from " + self.to_s # => "Hello from main"
Returns a new String containing integer copies of self:
"Ho! " * 3 # => "Ho! Ho! Ho! " "Ho! " * 0 # => ""
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"
Returns the substring of self specified by the arguments.
When the single Integer argument index is given, returns the 1-character substring found in self at offset index:
'bar'[2] # => "r"
Counts backward from the end of self if index is negative:
'foo'[-3] # => "f"
Returns nil if index is out of range:
'foo'[3] # => nil 'foo'[-4] # => nil
When the two Integer arguments start and length are given, returns the substring of the given length found in self at offset start:
'foo'[0, 2] # => "fo" 'foo'[0, 0] # => ""
Counts backward from the end of self if start is negative:
'foo'[-2, 2] # => "oo"
Special case: returns a new empty String if start is equal to the length of self:
'foo'[3, 2] # => ""
Returns nil if start is out of range:
'foo'[4, 2] # => nil 'foo'[-4, 2] # => nil
Returns the trailing substring of self if length is large:
'foo'[1, 50] # => "oo"
Returns nil if length is negative:
'foo'[0, -1] # => nil
When the single Range argument range is given, derives start and length values from the given range, and returns values as above:
'foo'[0..1] is equivalent to 'foo'[0, 2].
'foo'[0...1] is equivalent to 'foo'[0, 1].
When the Regexp argument regexp is given, and the capture argument is 0, returns the first matching substring found in self, or nil if none found:
'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 Integer capture group index or a String or Symbol capture group name; the method call returns only the specified capture (see Regexp Capturing):
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, nil is returned. If an invalid capture group name is given, IndexError is raised.
When the single String argument substring is given, returns the substring from self if found, otherwise nil:
'foo'['oo'] # => "oo" 'foo'['xx'] # => nil
String#slice is an alias for String#[].
Element Assignment—Replaces some or all of the content of str. The portion of the string affected is determined using the same criteria as String#[]. If the replacement string is not the same length as the text it is replacing, the string will be adjusted accordingly. If the regular expression or string is used as the index doesn’t match a position in the string, IndexError is raised. If the regular expression form is used, the optional second Integer allows you to specify which portion of the match to replace (effectively using the MatchData indexing rules. The forms that take an Integer will raise an IndexError if the value is out of range; the Range form will raise a RangeError, and the Regexp and String will raise an IndexError on negative match.
Returns the count of characters (not bytes) in self:
"\x80\u3042".length # => 2 "hello".length # => 5
String#size is an alias for String#length.
Related: String#bytesize.
Returns the count of bytes in self:
"\x80\u3042".bytesize # => 4 "hello".bytesize # => 5
Related: String#length.
Returns true if the length of self is zero, false otherwise:
"hello".empty? # => false " ".empty? # => false "".empty? # => true
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 Regexp-related global variables.
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"
Returns a Matchdata object (or nil) based on self and the given pattern.
Note: also updates Regexp-related global variables.
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
Returns true or false based on whether a match is found for self and pattern.
Note: does not update Regexp-related global variables.
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
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 # => ""
String#next is an alias for String#succ.
Equivalent to String#succ, but modifies self in place; returns self.
String#next! is an alias for String#succ!.
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 # => ""
String#next is an alias for String#succ.
Equivalent to String#succ, but modifies self in place; returns self.
String#next! is an alias for String#succ!.
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")>
Replaces the contents of self with the contents of other_string:
s = 'foo' # => "foo" s.replace('bar') # => "bar"
Returns a string containing the first character of self:
s = 'foo' # => "foo" s.chr # => "f"
Returns the byte at zero-based index as an integer:
s = 'abcde' # => "abcde" s.getbyte(0) # => 97 s.getbyte(1) # => 98
Related: String#setbyte.
Sets the byte at zero-based index to integer; returns integer:
s = 'abcde' # => "abcde" s.setbyte(0, 98) # => 98 s # => "bbcde"
Related: String#getbyte.
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>