From: Paul Lutus <nospam@...>
Date: 2006-10-28T02:50:20+09:00
Subject: Re: how to get only the duplicatet items from an array

Nico Landgraf wrote:

> i have an array like this
> aTemp =  [1, 1, 2, 2, 3, 4]
> and i want to know, which items are duplicatet.

/ ...

> so i found an bad solution and hope you can help me to get the right way.

#!/usr/bin/ruby -w

a = [1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 4, 5, 6, 7, 8, 9, 9, 9]

dups = []

hash = {}

a.each do |item|
  dups << item if hash[item]
  hash[item] = true
end

p dups

[1, 1, 1, 1, 2, 2, 2, 9, 9]

-- 
Paul Lutus
http://www.arachnoid.com