From: "David A. Black" <dblack@...>
Date: 2005-10-17T00:51:57+09:00
Subject: Re: How to get non-unique elements from an array?

Hi --

On Sun, 16 Oct 2005, Sam Kong wrote:

> Hello!
>
> I need to get non-unique elements from an array.
> The best I came up with was using a hash as a counter for each unique
> elements.
>
> a = [0,1,2,3,4,5,2,3]
>
> #What I want to get is [2,3] as 2,3 are non-unique elements.

One probably slow but kind of cool way is:

   a.uniq.find_all {|x| a.find_all {|y| y == x }.size > 1 }


David

-- 
David A. Black
dblack@wobblini.net