From: Kristof Bastiaensen <kristof@...>
Date: 2004-05-17T23:24:29+09:00
Subject: Re: RCR: More enumerator functionality

Hi,

On Mon, 17 May 2004 15:55:25 +0200, Robert Klemme wrote:
>>
>> what's wrong with
>> (1..3).select {|x| x[0]==0}.each {|x| p x}
>> ?
> 
> If the Enumerable contains a huge number of elements then this version
> will burn a lot of memory while in certain cases (e.g. printing) it is
> more efficient to be able to handle one element at a time only.
> 
> Well, of course in those cases you could simply do
> 
> (1..3).each {|x| p x if x[0]==0}
> 
> :-)
> 

That's indeed more elegant than with filter and lambdas.
The filter method would be only useful for implementing
enum_filter, maybe I will exclude it from the RCR.

Enum_filter would also behave like select, but it would
be more efficient for memory.  And you can keep the 
enumerable around it you need it later (even when the
original object has changed it's contents).

> Regards
> 
>     robert

Thanks,
Kristof