From: Mill Mill <koyakam@...>
Date: 2005-07-21T18:39:32+09:00
Subject: Re: List of removed items using Array#uniq

Mill Mill <koyakam <at> gmail.com> writes:

> 
> duplicates = all.uniq.select{|x|all.select{|y|y==x}.size>1}
> duplicate_with_count = all.inject(Hash.new(0)){|n,x|n[x]+=1;n}.select{|k,v|v>1}
> 
> hope this helps.
> 
> -mill
> 
> 

and this maybe better too:
duplicates_with_count=Hash.new(1)
s=all.sort
s.each_index{|i| duplicates_with_count[s[i]]+=1 if s[i]==s[i-1]}