From: "Frykholm, Niklas" <nfrykholm@...>
Date: 2001-10-09T17:57:41+09:00
Subject: [ruby-talk:22290] Re: [Newbie] Switching from Perl : suffling

[Pierre-Charles David]
>One of my teachers once showed me this method, which I find quite 
>elegant (although perhaps not very efficient because of the arrays 
>creation, but still O(n) ):
>
>module Enumerable
>   def shuffle
>     # Associate a random number to each element
>     pairs = self.collect { |item| [rand(), item] }
>     # Sort the pairs according to the random part
>     # and extract the original data
>     (pairs.sort { |x, y| x[0] <=> y[0] }).collect { |pair| pair[1] }
>   end
>end

Sorting is O(n log n).

// Niklas