Returns the new String formed by calling method #inspect on each array element:
a = [:foo, 'bar', 2] a.inspect # => "[:foo, \"bar\", 2]"
Array#to_s is an alias for Array#inspect.
Returns a new Array containing each element found both in self and in all of the given Arrays other_arrays; duplicates are omitted; items are compared using eql?:
[0, 1, 2, 3].intersection([0, 1, 2], [0, 1, 3]) # => [0, 1] [0, 0, 1, 1, 2, 3].intersection([0, 1, 2], [0, 1, 3]) # => [0, 1]
Preserves order from self:
[0, 1, 2].intersection([2, 1, 0]) # => [0, 1, 2]
Returns a copy of self if no arguments given.
Related: Array#&.
Returns true if the array and other_ary have at least one element in common, otherwise returns false:
a = [ 1, 2, 3 ] b = [ 3, 4, 5 ] c = [ 5, 6, 7 ] a.intersect?(b) #=> true a.intersect?(c) #=> false
Inserts given objects before or after the element at Integer index offset; returns self.
When index is non-negative, inserts all given objects before the element at offset index:
a = [:foo, 'bar', 2] a.insert(1, :bat, :bam) # => [:foo, :bat, :bam, "bar", 2]
Extends the array if index is beyond the array (index >= self.size):
a = [:foo, 'bar', 2] a.insert(5, :bat, :bam) a # => [:foo, "bar", 2, nil, nil, :bat, :bam]
Does nothing if no objects given:
a = [:foo, 'bar', 2] a.insert(1) a.insert(50) a.insert(-50) a # => [:foo, "bar", 2]
When index is negative, inserts all given objects after the element at offset index+self.size:
a = [:foo, 'bar', 2] a.insert(-2, :bat, :bam) a # => [:foo, "bar", :bat, :bam, 2]
Returns the index of a specified element.
When argument object is given but no block, returns the index of the first element element for which object == element:
a = [:foo, 'bar', 2, 'bar'] a.index('bar') # => 1
Returns nil if no such element found.
When both argument object and a block are given, calls the block with each successive element; returns the index of the first element for which the block returns a truthy value:
a = [:foo, 'bar', 2, 'bar'] a.index {|element| element == 'bar' } # => 1
Returns nil if the block never returns a truthy value.
When neither an argument nor a block is given, returns a new Enumerator:
a = [:foo, 'bar', 2] e = a.index e # => #<Enumerator: [:foo, "bar", 2]:index> e.each {|element| element == 'bar' } # => 1
Array#find_index is an alias for Array#index.
Related: rindex.
Returns the index of the last element for which object == element.
When argument object is given but no block, returns the index of the last such element found:
a = [:foo, 'bar', 2, 'bar'] a.rindex('bar') # => 3
Returns nil if no such object found.
When a block is given but no argument, calls the block with each successive element; returns the index of the last element for which the block returns a truthy value:
a = [:foo, 'bar', 2, 'bar'] a.rindex {|element| element == 'bar' } # => 3
Returns nil if the block never returns a truthy value.
When neither an argument nor a block is given, returns a new Enumerator:
a = [:foo, 'bar', 2, 'bar'] e = a.rindex e # => #<Enumerator: [:foo, "bar", 2, "bar"]:rindex> e.each {|element| element == 'bar' } # => 3
Related: index.
Returns the new String formed by joining the array elements after conversion. For each element element:
Uses element.to_s if element is not a kind_of?(Array).
Uses recursive element.join(separator) if element is a kind_of?(Array).
With no argument, joins using the output field separator, $,:
a = [:foo, 'bar', 2] $, # => nil a.join # => "foobar2"
With string argument separator, joins using that separator:
a = [:foo, 'bar', 2] a.join("\n") # => "foo\nbar\n2"
Joins recursively for nested Arrays:
a = [:foo, [:bar, [:baz, :bat]]] a.join # => "foobarbazbat"
Calls the block, if given, with each element of self; returns a new Array whose elements are the return values from the block:
a = [:foo, 'bar', 2] a1 = a.map {|element| element.class } a1 # => [Symbol, String, Integer]
Returns a new Enumerator if no block given:
a = [:foo, 'bar', 2] a1 = a.map a1 # => #<Enumerator: [:foo, "bar", 2]:map>
Array#collect is an alias for Array#map.
Calls the block, if given, with each element; replaces the element with the block’s return value:
a = [:foo, 'bar', 2] a.map! { |element| element.class } # => [Symbol, String, Integer]
Returns a new Enumerator if no block given:
a = [:foo, 'bar', 2] a1 = a.map! a1 # => #<Enumerator: [:foo, "bar", 2]:map!>
Array#collect! is an alias for Array#map!.
Returns true if for some index i in self, obj == self[i]; otherwise false:
[0, 1, 2].include?(2) # => true [0, 1, 2].include?(3) # => false
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)>
Builds a command line string from an argument list array joining all elements escaped for the Bourne shell and separated by a space.
See Shellwords.shelljoin for details.
Returns a string containing the place-value representation of self in radix base (in 2..36).
12345.to_s # => "12345" 12345.to_s(2) # => "11000000111001" 12345.to_s(8) # => "30071" 12345.to_s(10) # => "12345" 12345.to_s(16) # => "3039" 12345.to_s(36) # => "9ix" 78546939656932.to_s(36) # => "rubyrules"
Raises an exception if base is out of range.
Integer#inspect is an alias for Integer#to_s.
Since int is already an Integer, this always returns true.
Returns the absolute part of its polar form.
Complex(-1).abs #=> 1 Complex(3.0, -4.0).abs #=> 5.0
Returns the value as a string for inspection.
Complex(2).inspect #=> "(2+0i)" Complex('-8/6').inspect #=> "((-4/3)+0i)" Complex('1/2i').inspect #=> "(0+(1/2)*i)" Complex(0, Float::INFINITY).inspect #=> "(0+Infinity*i)" Complex(Float::NAN, Float::NAN).inspect #=> "(NaN+NaN*i)"
Returns true if cmp‘s real and imaginary parts are both finite numbers, otherwise returns false.
Always returns the string “nil”.
Returns the absolute value of self.
12.abs #=> 12 (-34.56).abs #=> 34.56 -34.56.abs #=> 34.56
Numeric#magnitude is an alias for Numeric#abs.