Like String#unpack, but unpacks and returns only the first extracted object. See Packed Data.
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)
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
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.==.
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.==.
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
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 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
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
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 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"
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
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
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 # => ""
Equivalent to String#succ, but modifies self in place; returns self.
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 # => ""
Equivalent to String#succ, but modifies self in place; returns self.
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"