From: Drew Olson <olsonas@...>
Date: 2006-10-13T01:05:09+09:00
Subject: Re: Isolating non-unique items in an array

Drew Olson wrote:
> Jason Burgett wrote:
>> I'm basically trying to the opposite of .uniq Let's say I have an array:
>> 
>> ["a", "a", "a", "b", "c", "d", "d"]
>> 
>> I would like to boil this down by first tossing the values that only 
>> appear once. Which leaves me with:
>> 
>> ["a", "a", "a", "d", "d"]
>> 
>> Then I need to somehow determine that "a" appears 3 times and "d" 
>> appears 2 times. Any help would be great. Thanks
> 
> This should work:
> 
> a = ["a", "a", "a", "b", "c", "d", "d"]
> a.uniq.map{|i| i if (a.map{|j| j if j==i}.length > 1)}

Actually, so that you have them appear more than once you'd need to do:

a = ["a", "a", "a", "b", "c", "d", "d"]
a.map{|i| i if (a.map{|j| j if j==i}.length > 1)}

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