From: "Marcin Mielżyński" <lopx@...>
Date: 2008-05-12T07:55:02+09:00
Subject: Re: Array#uniq with Hash elements... can't remove duplicates

andrea pisze:
> Hello,
> 
> I am having some trouble trying to remove duplicate data from an array
> of hashes. I've read on the pickaxe book that Array#uniq detects
> duplicates using the eql? method on the elements, but it doesn't seem to
> work even if I monkeypatch the Hash class:
> 
> class Hash
>   def eql? other
>     self == other
>   end
> end

you also need to define #hash method:

class Hash
   def eql? other
     self == other
   end

   def hash
     h = 0
     each_pair do |k, v|
         h ^= k.hash
         h *=137
         h ^= v.hash
     end
     h
   end
end


lopex