From: Simon Strandgaard <neoneye@...>
Date: 2005-10-18T01:41:51+09:00
Subject: Re: How to get non-unique elements from an array?

On 10/17/05, pauldacus@gmail.com <pauldacus@gmail.com> wrote:
> Young grasshoppers... let us never forget the power of the REGEX!  Let
> us not bother with counters or blocks... let us GSUB this bad boy!
>
> a = [0,1,2,3,4,5,2,3]
>
> a.sort.to_s.gsub(/(.)(\1)+/, '').split(//)
>
> =>["0", "1", "4", "5"]


no need to sort.. :-)

a = [0, 1, 2, 3, 4, 5, 2, 3]
a.to_s.delete(a.to_s.gsub(/(.)(?!.*\1)/,'')).split('').map{|i|i.to_i}
#=> [0, 1, 4, 5]

--
Simon Strandgaard