From: Sylvain Joyeux <sylvain.joyeux@...>
Date: 2008-09-22T17:26:10+09:00
Subject: Re: for or each?

On Sun, Sep 21, 2008 at 07:12:06AM +0900, Phlip wrote:
> tekwiz wrote:
>
>>>> It leaves you closer to a refactor to .map or .inject or .select or
>>>> .reject or .delete_if or .each_index or .each_with_index or ...
>
>> So, it's a code-readability issue and not a functional or complexity
>> issue?
>
> 'for' is arguably more readable. And it's not a performance issue - I 
> suspect the opcodes will be the same. It is very much a technical issue.
Nope. each { } needs one new scope for each iteration while "for ... in"
explicitely uses the parent scope... In the end, you create with #each
as many objects as there are in your collection - which can be a huge
performance hit in some cases. That's why I personally use "for ... in" in
performance-critical parts of my code, to avoid unnecessary GC.


Sylvain