Set Union — Returns a new array by joining other_arys with self, excluding any duplicates and preserving the order from the given arrays.
It compares elements using their hash and eql? methods for efficiency.
[ "a", "b", "c" ].union( [ "c", "d", "a" ] ) #=> [ "a", "b", "c", "d" ] [ "a" ].union( ["e", "b"], ["a", "c", "b"] ) #=> [ "a", "e", "b", "c" ] [ "a" ].union #=> [ "a" ]
See also Array#|.
Set Intersection — Returns a new array containing unique elements common to self and other_arys. Order is preserved from the original array.
It compares elements using their hash and eql? methods for efficiency.
[ 1, 1, 3, 5 ].intersection([ 3, 2, 1 ]) # => [ 1, 3 ] [ "a", "b", "z" ].intersection([ "a", "b", "c" ], [ "b" ]) # => [ "b" ] [ "a" ].intersection #=> [ "a" ]
See also Array#&.
Prepends objects to the front of self, moving other elements upwards. See also Array#shift for the opposite effect.
a = [ "b", "c", "d" ] a.unshift("a") #=> ["a", "b", "c", "d"] a.unshift(1, 2) #=> [ 1, 2, "a", "b", "c", "d"]
Inserts the given values before the element with the given index.
Negative indices count backwards from the end of the array, where -1 is the last element. If a negative index is used, the given values will be inserted after that element, so using an index of -1 will insert the values at the end of the array.
a = %w{ a b c d } a.insert(2, 99) #=> ["a", "b", 99, "c", "d"] a.insert(-2, 1, 2, 3) #=> ["a", "b", 99, "c", 1, 2, 3, "d"]
Invokes the given block once for each element of self.
Creates a new array containing the values returned by the block.
See also Enumerable#collect.
If no block is given, an Enumerator is returned instead.
a = [ "a", "b", "c", "d" ] a.collect {|x| x + "!"} #=> ["a!", "b!", "c!", "d!"] a.map.with_index {|x, i| x * i} #=> ["", "b", "cc", "ddd"] a #=> ["a", "b", "c", "d"]
Invokes the given block once for each element of self, replacing the element with the value returned by the block.
See also Enumerable#collect.
If no block is given, an Enumerator is returned instead.
a = [ "a", "b", "c", "d" ] a.map! {|x| x + "!" } a #=> [ "a!", "b!", "c!", "d!" ] a.collect!.with_index {|x, i| x[0...i] } a #=> ["", "b", "c!", "d!"]
Assumes that self is an array of arrays and transposes the rows and columns.
a = [[1,2], [3,4], [5,6]] a.transpose #=> [[1, 3, 5], [2, 4, 6]]
If the length of the subarrays don’t match, an IndexError is raised.
Returns a copy of self with all nil elements removed.
[ "a", nil, "b", nil, "c", nil ].compact #=> [ "a", "b", "c" ]
Removes nil elements from the array.
Returns nil if no changes were made, otherwise returns the array.
[ "a", nil, "b", nil, "c" ].compact! #=> [ "a", "b", "c" ] [ "a", "b", "c" ].compact! #=> nil
Returns the number of elements.
If an argument is given, counts the number of elements which equal obj using ==.
If a block is given, counts the number of elements for which the block returns a true value.
ary = [1, 2, 4, 2] ary.count #=> 4 ary.count(2) #=> 2 ary.count {|x| x%2 == 0} #=> 3
When invoked with a block, yield all permutations of length n of the elements of the array, then return the array itself.
If n is not specified, yield all permutations of all elements.
The implementation makes no guarantees about the order in which the permutations are yielded.
If no block is given, an Enumerator is returned instead.
Examples:
a = [1, 2, 3] a.permutation.to_a #=> [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]] a.permutation(1).to_a #=> [[1],[2],[3]] a.permutation(2).to_a #=> [[1,2],[1,3],[2,1],[2,3],[3,1],[3,2]] a.permutation(3).to_a #=> [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]] a.permutation(0).to_a #=> [[]] # one permutation of length 0 a.permutation(4).to_a #=> [] # no permutations of length 4
See also Enumerable#none?
See also Enumerable#one?
provides a unified clone operation, for REXML::XPathParser to use across multiple Object+ types
Returns a Hash containing implementation-dependent counters inside the VM.
This hash includes information about method/constant cache serials:
{
:global_method_state=>251,
:global_constant_state=>481,
:class_serial=>9029
}
The contents of the hash are implementation specific and may be changed in the future.
This method is only expected to work on C Ruby.
Returns a Digest subclass by name in a thread-safe manner even when on-demand loading is involved.
require 'digest' Digest("MD5") # => Digest::MD5 Digest(:SHA256) # => Digest::SHA256 Digest(:Foo) # => LoadError: library not found for class Digest::Foo -- digest/foo
provides a unified clone operation, for REXML::XPathParser to use across multiple Object types
Produces a shallow copy of obj—the instance variables of obj are copied, but not the objects they reference. clone copies the frozen (unless :freeze keyword argument is given with a false value) state of obj. See also the discussion under Object#dup.
class Klass attr_accessor :str end s1 = Klass.new #=> #<Klass:0x401b3a38> s1.str = "Hello" #=> "Hello" s2 = s1.clone #=> #<Klass:0x401b3998 @str="Hello"> s2.str[1,4] = "i" #=> "i" s1.inspect #=> "#<Klass:0x401b3a38 @str=\"Hi\">" s2.inspect #=> "#<Klass:0x401b3998 @str=\"Hi\">"
This method may have class-specific behavior. If so, that behavior will be documented under the #initialize_copy method of the class.
Returns object. This method is deprecated and will be removed in Ruby 3.2.
Returns false. This method is deprecated and will be removed in Ruby 3.2.
Returns object. This method is deprecated and will be removed in Ruby 3.2.
Returns a string containing a human-readable representation of obj. The default inspect shows the object’s class name, an encoding of the object id, and a list of the instance variables and their values (by calling inspect on each of them). User defined classes should override this method to provide a better representation of obj. When overriding this method, it should return a string whose encoding is compatible with the default external encoding.
[ 1, 2, 3..4, 'five' ].inspect #=> "[1, 2, 3..4, \"five\"]" Time.new.inspect #=> "2008-03-08 19:43:39 +0900" class Foo end Foo.new.inspect #=> "#<Foo:0x0300c868>" class Bar def initialize @bar = 1 end end Bar.new.inspect #=> "#<Bar:0x0300c868 @bar=1>"
Returns an array with both a numeric and a big represented as Bignum objects.
This is achieved by converting numeric to a Bignum.
A TypeError is raised if the numeric is not a Fixnum or Bignum type.
(0x3FFFFFFFFFFFFFFF+1).coerce(42) #=> [42, 4611686018427387904]
provides a unified clone operation, for REXML::XPathParser to use across multiple Object types
Returns a string containing the place-value representation of int with radix base (between 2 and 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"