Ruby 1.9.2 リファレンスマニュアル > ライブラリ一覧 > 組み込みライブラリ > Arrayクラス > repeated_permutation

instance method Array#repeated_permutation

repeated_permutation(n) { |p| block } -> Array

repeated_permutation(n) -> Enumerator

When invoked with a block, yield all repeated permutations of length <i>n</i> of the elements of <i>ary</i>, then return the array itself. The implementation makes no guarantees about the order in which the repeated permutations are yielded.

When invoked without a block, return an enumerator object 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

[SEE_ALSO] Array#repeated_combination, Array#permutation