Returns the imaginary value for self:
Complex.rect(7).imag # => 0 Complex.rect(9, -4).imag # => -4
If self was created with polar coordinates, the returned value is computed, and may be inexact:
Complex.polar(1, Math::PI/4).imag # => 0.7071067811865476 # Square root of 2.
Returns the absolute value (magnitude) for self; see polar coordinates:
Complex.polar(-1, 0).abs # => 1.0
If self was created with rectangular coordinates, the returned value is computed, and may be inexact:
Complex.rectangular(1, 1).abs # => 1.4142135623730951 # The square root of 2.
Returns a string representation of self:
Complex.rect(2).inspect # => "(2+0i)" Complex.rect(-8, 6).inspect # => "(-8+6i)" Complex.rect(0, Rational(1, 2)).inspect # => "(0+(1/2)*i)" Complex.rect(0, Float::INFINITY).inspect # => "(0+Infinity*i)" Complex.rect(Float::NAN, Float::NAN).inspect # => "(NaN+NaN*i)"
Returns true if both self.real.finite? and self.imag.finite? are true, false otherwise:
Complex.rect(1, 1).finite? # => true Complex.rect(Float::INFINITY, 0).finite? # => false
Related: Numeric#finite?, Float#finite?.
Returns the absolute value of self.
12.abs #=> 12 (-34.56).abs #=> 34.56 -34.56.abs #=> 34.56
Returns true if self is a finite number, false otherwise.
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"
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 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.
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.
Related: String#index, String#byterindex.
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.
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.
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\""
Forms substrings (“lines”) of self according to the given arguments (see String#each_line for details); returns the lines in an array.
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]
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 self contains other_string, false otherwise:
s = 'foo' s.include?('f') # => true s.include?('fo') # => true s.include?('food') # => false
Returns the Encoding object that represents the encoding of obj.
Returns true if self is not Infinity, -Infinity, or NaN, false otherwise:
f = 2.0 # => 2.0 f.finite? # => true f = 1.0/0.0 # => Infinity f.finite? # => false f = -1.0/0.0 # => -Infinity f.finite? # => false f = 0.0/0.0 # => NaN f.finite? # => false
Returns a string containing a representation of self; depending of the value of self, the string representation may contain:
A fixed-point number.
A number in “scientific notation” (containing an exponent).
‘Infinity’.
‘-Infinity’.
‘NaN’ (indicating not-a-number).
3.14.to_s # => “3.14” (10.1**50).to_s # => “1.644631821843879e+50” (10.1**500).to_s # => “Infinity” (-10.1**500).to_s # => “-Infinity” (0.0/0.0).to_s # => “NaN”