From: Robert Klemme <shortcutter@...>
Date: 2007-01-23T07:40:06+09:00
Subject: Re: array equality question

On 22.01.2007 23:27, Chris McMahon wrote:
> This took me by surprise:
> 
> irb(main):001:0> a1 = ['x','y','z']
> => ["x", "y", "z"]
> irb(main):002:0> a2 = ['y','z','x']
> => ["y", "z", "x"]
> 
> irb(main):008:0> puts "yo" if a1 == a2
> => nil
> irb(main):009:0> puts "yo" if a1 != a2
> yo
> => nil
> 
> I assumed order of elements would not be considered for equality.  Is
> there any particular reason for this behavior?

Why should order not matter?  An array is an *ordered* list of elements 
as indexing by position indicates.  a1[0] == a2[0] will return false, 
why then should a1 == a2 return true?

If you to ignore order you either have to compare sorted copies or 
resort to Set.

Kind regards

	robert