From: "David A. Black" <dblack@...>
Date: 2007-08-21T01:06:38+09:00
Subject: Re: Detecting duplicates in an array, anything in the standard library ?

Hi --

On Tue, 21 Aug 2007, Gabriel Dragffy wrote:

>
> On 20 Aug 2007, at 14:50, Robert Klemme wrote:
>
>>> 
>>> require 'set'
>>> 
>>> new_ary = ary.to_set.to_a #set strips dups.
>> 
>> It does, but as far as I can see OP wanted exactly the duplicates back.
>> 
>> Cheers
>> 
>> robert
>> 
>
>
> I'm a n00b, sorry if I'm poking nose in. Couldn't the op do something using 
> &, like so:
>
> [1,2,3] & [2,3,4]  == [2,3]

The original question was how to get all dups occurring in one array:

   [1,2,3,2,4,5,5,6]   => [2,5]


David

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