From: "Wolfgang Nádasi-Donner" <ed.odanow@...>
Date: 2007-08-19T21:06:54+09:00
Subject: Re: Detecting duplicates in an array, anything in the standa

David A. Black wrote:
> Hi --
> 
> On Sun, 19 Aug 2007, Wolfgang Nádasi-Donner wrote:
> 
>> : [r[0], r[1][1..-1]]}[0].uniq # => ["c"]
> How about:
> 
>    >>  a = [1,2,3,4,5,4,2,2]
>    => [1, 2, 3, 4, 5, 4, 2, 2]
>    >> a.inject([]) {|acc,e| acc << e unless acc.include?(e); acc }
>    => [1, 2, 3, 4, 5]
> 
> 
> David

The problem is, that he wants all non unique elements. Unfortunately the 
difference of two arrays doesn't care about double elements, 
otherwise...

irb(main):004:0> a
=> [1, 2, 3, 4, 5, 4, 2, 2]
irb(main):005:0> b
=> [1, 2, 3, 4, 5]
irb(main):006:0> a-b
=> []

...would work. My solution is not recommended at all - it's sunday after 
lunch time, and I had the decision between cleaning the dishes or to do 
some nice things before...

Wolfgang Nádasi-Donner
-- 
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