From: SonOfLilit <sonoflilit@...>
Date: 2007-05-30T22:46:33+09:00
Subject: Re: Enumerable#serially - those nifty functions w/o memory footprint

Sorry, found a bug, I'll need to make it into this:

module Enumerable
  def serially(&b)
    a = []
    self.each{|x| t = ([x].instance_eval(&b); a << b[0] unless b.empty?}
    # notice, relevance to "it" discussion that's currently going on, just btw
  end
end


On 5/30/07, SonOfLilit <sonoflilit@gmail.com> wrote:
> Hello,
>
> I've seen many people write things like:
>
> (1..1000000).to_a. # anything that is a huge enumerable can work as an example
>   collect{|x| num_appearances(x)}.select{|x|
> x.is_norwegian?}.collect{|x| x.paycheck}.each{|x| p x}
>
> I almost wrote something like that myself today.
>
> The problem, of course, is the huge memory footprint - collect,
> select, collect each creates a new temporary array to store the
> results in.
>
> Here's a solution to that problem, exchanging it for a bit of speed
> (anything that uses those methods could obviously live with that,
> otherwise another language or method would be used):
>
> module Enumerable
>   def serially(&b)
>     self.collect{|x| *([x].instance_eval(&b)}
>   end
> end
>
> Just beware not to use it with sort or any of the "!" methods or with
> sort or sort_by.
>
> Aur
>
>