From: Eric Kidd <emk.lists@...>
Date: 2006-03-23T07:37:19+09:00
Subject: Re: duplicate keys in a Hash

On Mar 22, 2006, at 3:56 PM, Brian Buckley wrote:
> In the code below it appears Ruby is permitting duplicate keys.   
> What's
> happening?
> --Brian
>
> h = {}
> h[{}] = "test1" #key is an empty hash
> h[{}] = "test2" #2nd key is an empty hash  -- two duplicate keys?
> h.size # 2
>
> {} == {}  # => true empty hashes are equal

The two empty hashes are equal, but they're not the same empty hash,  
if that makes sense. Try this:

irb(main):013:0> {}.object_id == {}.object_id
=> false

I hope this answers your question!

Cheers,
Eric