Calls the block, if given, with combinations of elements of self; returns self. The order of combinations is indeterminate.
When a block and an in-range positive Integer argument n (0 < n <= self.size) are given, calls the block with all n-tuple combinations of self.
Example:
a = [0, 1, 2] a.combination(2) {|combination| p combination }
Output:
[0, 1] [0, 2] [1, 2]
Another example:
a = [0, 1, 2] a.combination(3) {|combination| p combination }
Output:
[0, 1, 2]
When n is zero, calls the block once with a new empty Array:
a = [0, 1, 2] a1 = a.combination(0) {|combination| p combination }
Output:
[]
When n is out of range (negative or larger than self.size), does not call the block:
a = [0, 1, 2] a.combination(-1) {|combination| fail 'Cannot happen' } a.combination(4) {|combination| fail 'Cannot happen' }
Returns a new Enumerator if no block given:
a = [0, 1, 2] a.combination(2) # => #<Enumerator: [0, 1, 2]:combination(2)>
Returns a new Array containing the first n element of self, where n is a non-negative Integer; does not modify self.
Examples:
a = [0, 1, 2, 3, 4, 5] a.take(1) # => [0] a.take(2) # => [0, 1] a.take(50) # => [0, 1, 2, 3, 4, 5] a # => [0, 1, 2, 3, 4, 5]
Returns self truncated (toward zero) to a precision of ndigits decimal digits.
When ndigits is negative, the returned value has at least ndigits.abs trailing zeros:
555.truncate(-1) # => 550 555.truncate(-2) # => 500 -555.truncate(-2) # => -500
Returns self when ndigits is zero or positive.
555.truncate # => 555 555.truncate(50) # => 555
Related: Integer#round.
Returns self.
Returns 1.
Returns the value as a rational. The optional argument eps is always ignored.
Return the class or module refined by the receiver.
module M refine String do end end M.refinements[0].target # => String
Returns a new Complex object formed from the arguments, each of which must be an instance of Numeric, or an instance of one of its subclasses: Complex, Float, Integer, Rational; see Rectangular Coordinates:
Complex.rect(3) # => (3+0i) Complex.rect(3, Math::PI) # => (3+3.141592653589793i) Complex.rect(-3, -Math::PI) # => (-3-3.141592653589793i)
Complex.rectangular is an alias for Complex.rect.
Returns the array [self.real, self.imag]:
Complex.rect(1, 2).rect # => [1, 2]
If self was created with polar coordinates, the returned value is computed, and may be inexact:
Complex.polar(1.0, 1.0).rect # => [0.5403023058681398, 0.8414709848078965]
Complex#rectangular is an alias for Complex#rect.
Returns the conjugate of self, Complex.rect(self.imag, self.real):
Complex.rect(1, 2).conj # => (1-2i)
Returns the Complex object created from the numerators of the real and imaginary parts of self, after converting each part to the lowest common denominator of the two:
c = Complex(Rational(2, 3), Rational(3, 4)) # => ((2/3)+(3/4)*i) c.numerator # => (8+9i)
In this example, the lowest common denominator of the two parts is 12; the two converted parts may be thought of as Rational(8, 12) and Rational(9, 12), whose numerators, respectively, are 8 and 9; so the returned value of c.numerator is Complex(8, 9).
Related: Complex#denominator.
Returns the denominator of self, which is the least common multiple of self.real.denominator and self.imag.denominator:
Complex.rect(Rational(1, 2), Rational(2, 3)).denominator # => 6
Note that n.denominator of a non-rational numeric is 1.
Related: Complex#numerator.
Returns a Rational object whose value is exactly or approximately equivalent to that of self.real.
With no argument epsilon given, returns a Rational object whose value is exactly equal to that of self.real.rationalize:
Complex(1, 0).rationalize # => (1/1) Complex(1, Rational(0, 1)).rationalize # => (1/1) Complex(3.14159, 0).rationalize # => (314159/100000)
With argument epsilon given, returns a Rational object whose value is exactly or approximately equal to that of self.real to the given precision:
Complex(3.14159, 0).rationalize(0.1) # => (16/5) Complex(3.14159, 0).rationalize(0.01) # => (22/7) Complex(3.14159, 0).rationalize(0.001) # => (201/64) Complex(3.14159, 0).rationalize(0.0001) # => (333/106) Complex(3.14159, 0).rationalize(0.00001) # => (355/113) Complex(3.14159, 0).rationalize(0.000001) # => (7433/2366) Complex(3.14159, 0).rationalize(0.0000001) # => (9208/2931) Complex(3.14159, 0).rationalize(0.00000001) # => (47460/15107) Complex(3.14159, 0).rationalize(0.000000001) # => (76149/24239) Complex(3.14159, 0).rationalize(0.0000000001) # => (314159/100000) Complex(3.14159, 0).rationalize(0.0) # => (3537115888337719/1125899906842624)
Related: Complex#to_r.
Returns zero as a Rational:
nil.rationalize # => (0/1)
Argument eps is ignored.
Returns array [self, 0].
Returns self truncated (toward zero) to a precision of digits decimal digits.
Numeric implements this by converting self to a Float and invoking Float#truncate.
Returns true if self is less than 0, false otherwise.
Returns self.
Returns the numerator.
Returns the denominator (always positive).
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 a string containing the characters in self; the first character is upcased; the remaining characters are downcased:
s = 'hello World!' # => "hello World!" s.capitalize # => "Hello world!"
The casing may be affected by the given options; see Case Mapping.
Related: String#capitalize!.
Upcases the first character in self; downcases the remaining characters; returns self if any changes were made, nil otherwise:
s = 'hello World!' # => "hello World!" s.capitalize! # => "Hello world!" s # => "Hello world!" s.capitalize! # => nil
The casing may be affected by the given options; see Case Mapping.
Related: String#capitalize.
Concatenates each object in objects to self and returns self:
s = 'foo' s.concat('bar', 'baz') # => "foobarbaz" s # => "foobarbaz"
For each given object object that is an Integer, the value is considered a codepoint and converted to a character before concatenation:
s = 'foo' s.concat(32, 'bar', 32, 'baz') # => "foo bar baz"
Related: String#<<, which takes a single argument.