From: "ara.t.howard" <ara.t.howard@...>
Date: 2008-04-12T05:31:19+09:00
Subject: Re: delete_if, select and (lack of) delete_if!, self.POLS == false


On Apr 11, 2008, at 2:07 PM, Saku Ytti wrote:
> I see what you mean, and I fully agree that changing existing
> methods would cause lot of inconvenience. Kinda just wish this
> functionality would be built-in (for performnce reasons), and
> select!, reject!, delete_if! might be feasible candidates from
> different points of view, if there wasn't history as a burden.
> Anyhow than you for your insight.


think about that

   [0, 1, 2, 3].reject!{|i| i.odd}

is going to do mutiple array replacements, so

   [0,2,3]
   [0,3]

shuffling an array like that all the way would KILL performance.  you  
need to build a new array and then replace all at once.  of course  
that is already there

   a.replace a.select{|i| i.odd?}

which reads clearly and doesn't degrade to exponential array  
shuffling...

food for though

a @ http://codeforpeople.com/
--
we can deny everything, except that we have the possibility of being  
better. simply reflect on that.
h.h. the 14th dalai lama