A String object holds and manipulates an arbitrary sequence of bytes, typically representing characters. String objects may be created using String::new or as literals.
Because of aliasing issues, users of strings should be aware of the methods that modify the contents of a String object. Typically, methods with names ending in “!” modify their receiver, while those without a “!” return a new String. However, there are exceptions, such as String#[]=.
Returns the string being scanned.
Returns a frozen copy of the string passed in to match.
m = /(.)(.)(\d+)(\d)/.match("THX1138.") m.string #=> "THX1138."
Returns arg as a String.
First tries to call its to_str method, then its to_s method.
String(self) #=> "main" String(self.class) #=> "Object" String(123456) #=> "123456"
Returns a copy of the receiver with leading and trailing whitespace removed.
Whitespace is defined as any of the following characters: null, horizontal tab, line feed, vertical tab, form feed, carriage return, space.
" hello ".strip #=> "hello" "\tgoodbye\r\n".strip #=> "goodbye" "\x00\t\n\v\f\r ".strip #=> "" "hello".strip #=> "hello"
Returns a copy of the receiver with leading whitespace removed. See also String#rstrip and String#strip.
Refer to String#strip for the definition of whitespace.
" hello ".lstrip #=> "hello " "hello".lstrip #=> "hello"
Returns a copy of the receiver with trailing whitespace removed. See also String#lstrip and String#strip.
Refer to String#strip for the definition of whitespace.
" hello ".rstrip #=> " hello" "hello".rstrip #=> "hello"
Removes leading and trailing whitespace from the receiver. Returns the altered receiver, or nil if there was no change.
Refer to String#strip for the definition of whitespace.
" hello ".strip! #=> "hello" "hello".strip! #=> nil
Removes leading whitespace from the receiver. Returns the altered receiver, or nil if no change was made. See also String#rstrip! and String#strip!.
Refer to String#strip for the definition of whitespace.
" hello ".lstrip! #=> "hello " "hello ".lstrip! #=> nil "hello".lstrip! #=> nil
Removes trailing whitespace from the receiver. Returns the altered receiver, or nil if no change was made. See also String#lstrip! and String#strip!.
Refer to String#strip for the definition of whitespace.
" hello ".rstrip! #=> " hello" " hello".rstrip! #=> nil "hello".rstrip! #=> nil
Returns the index of the last occurrence of the given substring or pattern (regexp) in str. Returns nil if not found. If the second parameter is present, it specifies the position in the string to end the search—characters beyond this point will not be considered.
"hello".rindex('e') #=> 1 "hello".rindex('l') #=> 3 "hello".rindex('a') #=> nil "hello".rindex(?e) #=> 1 "hello".rindex(/[aeiou]/, -2) #=> 1
Returns the Encoding object that represents the encoding of obj.
Inserts other_str before the character at the given index, modifying str. Negative indices count from the end of the string, and insert after the given character. The intent is insert aString so that it starts at the given index.
"abcd".insert(0, 'X') #=> "Xabcd" "abcd".insert(3, 'X') #=> "abcXd" "abcd".insert(4, 'X') #=> "abcdX" "abcd".insert(-3, 'X') #=> "abXcd" "abcd".insert(-1, 'X') #=> "abcdX"
Returns the character length of str.
Returns the index of the first occurrence of the given substring or pattern (regexp) in str. Returns nil if not found. If the second parameter is present, it specifies the position in the string to begin the search.
"hello".index('e') #=> 1 "hello".index('lo') #=> 3 "hello".index('a') #=> nil "hello".index(?e) #=> 1 "hello".index(/[aeiou]/, -3) #=> 4
Returns a printable version of str, surrounded by quote marks, with special characters escaped.
str = "hello" str[3] = "\b" str.inspect #=> "\"hel\\bo\""
Returns an array of lines in str split using the supplied record separator ($/ by default). This is a shorthand for str.each_line(separator, getline_args).to_a.
See IO.readlines for details about getline_args.
"hello\nworld\n".lines #=> ["hello\n", "world\n"] "hello world".lines(' ') #=> ["hello ", " ", "world"] "hello\nworld\n".lines(chomp: true) #=> ["hello", "world"]
If a block is given, which is a deprecated form, works the same as each_line.
Returns an array of the Integer ordinals of the characters in str. This is a shorthand for str.each_codepoint.to_a.
If a block is given, which is a deprecated form, works the same as each_codepoint.
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"
Returns true if str contains the given string or character.
"hello".include? "lo" #=> true "hello".include? "ol" #=> false "hello".include? ?h #=> true
If integer is greater than the length of str, returns a new String of length integer with str left justified and padded with padstr; otherwise, returns str.
"hello".ljust(4) #=> "hello" "hello".ljust(20) #=> "hello " "hello".ljust(20, '1234') #=> "hello123412341234123"