From: Timothy Hunter <TimHunter@...>
Date: 2006-10-13T09:18:37+09:00
Subject: Re: Hash & keys...

S辿bastien Wautelet wrote:
> I'm having some trouble understanding how hashes work in Ruby. Consider 
> the following test :
>
> irb(main):002:0> v=Vector[4,5]
> => Vector[4, 5]
> irb(main):003:0> v2=Vector[4,5]
> => Vector[4, 5]
> irb(main):004:0> v==v2
> => true
> irb(main):005:0> v.hash
> => 17
> irb(main):006:0> v2.hash
> => 17
> irb(main):007:0> h=Hash.new
> => {}
> irb(main):008:0> h[v]="whatever is in (4,5)"
> => "whatever is in (4,5)"
> irb(main):009:0> h[v2]
> => nil
>
> I'd have expected h[v2] => "whatever is in (4,5)", since v==v2 and both 
> have the same hash value... what am I doing wrong?
>
>   
It's not enough that they have the same hash value or that obj1 == obj2. 
For the purposes of Hash, two objects are the same if obj1.eql?(obj2). 
Does v1.eql?(v2)?