From: Nico Landgraf <nico@...>
Date: 2006-10-28T03:00:17+09:00
Subject: Re: how to get only the duplicatet items from an array

thanks paul,

looks like my way.
i hoped there is a smarter way in ruby.

Paul Lutus wrote:
> 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]
>