Results for: "Array"

Replaces the contents of self with the contents of other_ary, truncating or expanding if necessary.

a = [ "a", "b", "c", "d", "e" ]
a.replace([ "x", "y", "z" ])   #=> ["x", "y", "z"]
a                              #=> ["x", "y", "z"]

Returns self.

If called on a subclass of Array, converts the receiver to an Array object.

Returns the result of interpreting ary as an array of [key, value] pairs.

[[:foo, :bar], [1, 2]].to_h
  # => {:foo => :bar, 1 => 2}

If a block is given, the results of the block on each element of the array will be used as pairs.

["foo", "bar"].to_h {|s| [s.ord, s]}
  # => {102=>"foo", 98=>"bar"}

Same as Array#each, but passes the index of the element instead of the element itself.

An Enumerator is returned if no block is given.

a = [ "a", "b", "c" ]
a.each_index {|x| print x, " -- " }

produces:

0 -- 1 -- 2 --

Same as Array#each, but traverses self in reverse order.

a = [ "a", "b", "c" ]
a.reverse_each {|x| print x, " " }

produces:

c b a

Returns the index of the first object in ary such that the object is == to obj.

If a block is given instead of an argument, returns the index of the first object for which the block returns true. Returns nil if no match is found.

See also Array#rindex.

An Enumerator is returned if neither a block nor argument is given.

a = [ "a", "b", "c" ]
a.index("b")              #=> 1
a.index("z")              #=> nil
a.index {|x| x == "b"}    #=> 1

Sorts self in place using a set of keys generated by mapping the values in self through the given block.

The result is not guaranteed to be stable. When two keys are equal, the order of the corresponding elements is unpredictable.

If no block is given, an Enumerator is returned instead.

See also Enumerable#sort_by.

Deletes every element of self for which the given block evaluates to false, and returns self.

If no block is given, an Enumerator is returned instead.

a = %w[ a b c d e f ]
a.keep_if {|v| v =~ /[aeiou]/ }    #=> ["a", "e"]
a                                  #=> ["a", "e"]

See also Array#select!.

Returns an array containing the elements in self corresponding to the given selector(s).

The selectors may be either integer indices or ranges.

See also Array#select.

a = %w{ a b c d e f }
a.values_at(1, 3, 5)          # => ["b", "d", "f"]
a.values_at(1, 3, 5, 7)       # => ["b", "d", "f", nil]
a.values_at(-1, -2, -2, -7)   # => ["f", "e", "e", nil]
a.values_at(4..6, 3...6)      # => ["e", "f", nil, "d", "e", "f"]

Deletes the element at the specified index, returning that element, or nil if the index is out of range.

See also Array#slice!

a = ["ant", "bat", "cat", "dog"]
a.delete_at(2)    #=> "cat"
a                 #=> ["ant", "bat", "dog"]
a.delete_at(99)   #=> nil

Deletes every element of self for which block evaluates to true.

The array is changed instantly every time the block is called, not after the iteration is over.

See also Array#reject!

If no block is given, an Enumerator is returned instead.

scores = [ 97, 42, 75 ]
scores.delete_if {|score| score < 80 }   #=> [97]

When invoked with a block, yield all repeated permutations of length n of the elements of the array, then return the array itself.

The implementation makes no guarantees about the order in which the repeated permutations are yielded.

If no block is given, an Enumerator is returned instead.

Examples:

a = [1, 2]
a.repeated_permutation(1).to_a  #=> [[1], [2]]
a.repeated_permutation(2).to_a  #=> [[1,1],[1,2],[2,1],[2,2]]
a.repeated_permutation(3).to_a  #=> [[1,1,1],[1,1,2],[1,2,1],[1,2,2],
                                #    [2,1,1],[2,1,2],[2,2,1],[2,2,2]]
a.repeated_permutation(0).to_a  #=> [[]] # one permutation of length 0

When invoked with a block, yields all repeated combinations of length n of elements from the array and then returns the array itself.

The implementation makes no guarantees about the order in which the repeated combinations are yielded.

If no block is given, an Enumerator is returned instead.

Examples:

a = [1, 2, 3]
a.repeated_combination(1).to_a  #=> [[1], [2], [3]]
a.repeated_combination(2).to_a  #=> [[1,1],[1,2],[1,3],[2,2],[2,3],[3,3]]
a.repeated_combination(3).to_a  #=> [[1,1,1],[1,1,2],[1,1,3],[1,2,2],[1,2,3],
                                #    [1,3,3],[2,2,2],[2,2,3],[2,3,3],[3,3,3]]
a.repeated_combination(4).to_a  #=> [[1,1,1,1],[1,1,1,2],[1,1,1,3],[1,1,2,2],[1,1,2,3],
                                #    [1,1,3,3],[1,2,2,2],[1,2,2,3],[1,2,3,3],[1,3,3,3],
                                #    [2,2,2,2],[2,2,2,3],[2,2,3,3],[2,3,3,3],[3,3,3,3]]
a.repeated_combination(0).to_a  #=> [[]] # one combination of length 0

Passes elements to the block until the block returns nil or false, then stops iterating and returns an array of all prior elements.

If no block is given, an Enumerator is returned instead.

See also Array#drop_while

a = [1, 2, 3, 4, 5, 0]
a.take_while {|i| i < 3}    #=> [1, 2]

Drops elements up to, but not including, the first element for which the block returns nil or false and returns an array containing the remaining elements.

If no block is given, an Enumerator is returned instead.

See also Array#take_while

a = [1, 2, 3, 4, 5, 0]
a.drop_while {|i| i < 3 }   #=> [3, 4, 5, 0]

Creates a string representation of self.

[ "a", "b", "c" ].to_s     #=> "[\"a\", \"b\", \"c\"]"

This string is put at the end of a line that holds a JSON array.

This string is put at the end of a line that holds a JSON array.