With a block given, returns a new array whose elements are all those from self for which the block returns false or nil:
a = [:foo, 'bar', 2, 'bat'] a1 = a.reject {|element| element.to_s.start_with?('b') } a1 # => [:foo, 2]
With no block given, returns a new Enumerator.
Related: Methods for Fetching.
With a block given, calls the block with each element of self; removes each element for which the block returns a truthy value.
Returns self if any elements removed:
a = [:foo, 'bar', 2, 'bat'] a.reject! {|element| element.to_s.start_with?('b') } # => [:foo, 2]
Returns nil if no elements removed.
With no block given, returns a new Enumerator.
Related: see Methods for Deleting.
Replaces the elements of self with the elements of other_array, which must be an array-convertible object; returns self:
a = ['a', 'b', 'c'] # => ["a", "b", "c"] a.replace(['d', 'e']) # => ["d", "e"]
Related: see Methods for Assigning.
Freezes self (if not already frozen); returns self:
a = [] a.frozen? # => false a.freeze a.frozen? # => true
No further changes may be made to self; raises FrozenError if a change is attempted.
Related: Kernel#frozen?.
Prepends the given objects to self:
a = [:foo, 'bar', 2] a.unshift(:bam, :bat) # => [:bam, :bat, :foo, "bar", 2]
Related: Array#shift; see also Methods for Assigning.
Returns the predecessor of self (equivalent to self - 1):
1.pred #=> 0 -1.pred #=> -2
Related: Integer#succ (successor value).
Returns self modulo other as a real number.
For integer n and real number r, these expressions are equivalent:
n % r n-r*(n/r).floor n.divmod(r)[1]
See Numeric#divmod.
Examples:
10 % 2 # => 0 10 % 3 # => 1 10 % 4 # => 2 10 % -2 # => 0 10 % -3 # => -2 10 % -4 # => -2 10 % 3.0 # => 1.0 10 % Rational(3, 1) # => (1/1)
Returns a 2-element array [q, r], where
q = (self/other).floor # Quotient r = self % other # Remainder
Examples:
11.divmod(4) # => [2, 3] 11.divmod(-4) # => [-3, -1] -11.divmod(4) # => [-3, 1] -11.divmod(-4) # => [2, -3] 12.divmod(4) # => [3, 0] 12.divmod(-4) # => [-3, 0] -12.divmod(4) # => [-3, 0] -12.divmod(-4) # => [3, 0] 13.divmod(4.0) # => [3, 1.0] 13.divmod(Rational(4, 1)) # => [3, (1/1)]
Returns true if self is an even number, false otherwise.
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 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 real value for self:
Complex.rect(7).real # => 7 Complex.rect(9, -4).real # => 9
If self was created with polar coordinates, the returned value is computed, and may be inexact:
Complex.polar(1, Math::PI/4).real # => 0.7071067811865476 # Square root of 2.
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 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 false; for compatibility with Numeric#real?.
Returns array [self, 0].
Returns array [self, 0].
Returns a 2-element array [q, r], where
q = (self/other).floor # Quotient r = self % other # Remainder
Of the Core and Standard Library classes, only Rational uses this implementation.
Examples:
Rational(11, 1).divmod(4) # => [2, (3/1)] Rational(11, 1).divmod(-4) # => [-3, (-1/1)] Rational(-11, 1).divmod(4) # => [-3, (1/1)] Rational(-11, 1).divmod(-4) # => [2, (-3/1)] Rational(12, 1).divmod(4) # => [3, (0/1)] Rational(12, 1).divmod(-4) # => [-3, (0/1)] Rational(-12, 1).divmod(4) # => [-3, (0/1)] Rational(-12, 1).divmod(-4) # => [3, (0/1)] Rational(13, 1).divmod(4.0) # => [3, 1.0] Rational(13, 1).divmod(Rational(4, 11)) # => [35, (3/11)]
Returns self modulo other as a real number.
Of the Core and Standard Library classes, only Rational uses this implementation.
For Rational r and real number n, these expressions are equivalent:
r % n r-n*(r/n).floor r.divmod(n)[1]
See Numeric#divmod.
Examples:
r = Rational(1, 2) # => (1/2) r2 = Rational(2, 3) # => (2/3) r % r2 # => (1/2) r % 2 # => (1/2) r % 2.0 # => 0.5 r = Rational(301,100) # => (301/100) r2 = Rational(7,5) # => (7/5) r % r2 # => (21/100) r % -r2 # => (-119/100) (-r) % r2 # => (119/100) (-r) %-r2 # => (-21/100)
Returns true if self is greater than 0, false otherwise.
Returns true if self is less than 0, false otherwise.
Returns true if self is a real number (i.e. not Complex).
Returns self.
Returns true if the length of self is zero, false otherwise:
"hello".empty? # => false " ".empty? # => false "".empty? # => true
Replaces the contents of self with the contents of other_string:
s = 'foo' # => "foo" s.replace('bar') # => "bar"