From: matz@... (Yukihiro Matsumoto)
Date: 2003-02-21T04:18:24+09:00
Subject: Re: Inconsistent behavior in Array methods

Hi,

In message "Inconsistent behavior in Array methods"
    on 03/02/21, "Warren Brown" <wkb@airmail.net> writes:

|    I recently tracked down a bug in my code to a line that read:
|
|        cards = cards.sort.uniq
|
|    This seemed perfectly reasonable - the cards array contained Card
|objects which were Enumerable.  However, the bug was due to the fact that
|Array#uniq does not use the object's == method to do comparisons - even
|though Array#sort uses the object's <=> method.  Upon investigation, I found
|that the implementation of Array#uniq uses a hash, and since the key to the
|hash is the object ID, uniqueness ends up being defined as (obj1.id ==
|obj2.id).  This was *surprising* to me.

I know, but I thought the order of execution time was more important,
especially for big arrays.

							matz.