From: "Peña, Botp" <botp@...>
Date: 2008-07-07T14:13:12+09:00
Subject: Re: Array Combinations

From: Pragash Mr. [mailto:gananapragasam@srishtisoft.com] 
# i am having an array for ex:[1,2,3,4]
# from this array i want to find the possible combinations like
# [1,3,4,2]
# [1,4,2,3]
# etc....

if you have ruby version 1.8.7 or 1.9, just try it

eg,

> RUBY_VERSION
=> "1.8.7"

> [1,2,3].permutation(3){|x| p x}
[1, 2, 3]
[1, 3, 2]
[2, 1, 3]
[2, 3, 1]
[3, 1, 2]
[3, 2, 1]
=> [1, 2, 3]

> [1,2,3].permutation(2){|x| p x}
[1, 2]
[1, 3]
[2, 1]
[2, 3]
[3, 1]
[3, 2]
=> [1, 2, 3]

> [1,2,3].combination(3){|x| p x}
[1, 2, 3]
=> [1, 2, 3]

> [1,2,3].combination(2){|x| p x}
[1, 2]
[1, 3]
[2, 3]
=> [1, 2, 3]

kind regards -botp