From: Robert Klemme <shortcutter@...>
Date: 2009-01-29T17:05:49+09:00
Subject: Re: Real life use of each_cons?

2009/1/29 Mischa Fierer <f.mischa@gmail.com>:
> Hello,
>
> I've been going through the enumerable/enumerator methods that I'm
> unfamiliar with and came across each_cons. Apart from a post by a guy
> who wasn't sure where it was even defined, I have only come across one
> use of it in the wild:
>
> (From Prawn)
>
>  def polygon(*points)
>      move_to points[0]
>      (points << points[0]).each_cons(2) do |p1,p2|
>        line_to(*p2)
>      end
>    end
>
>
> Does anyone have any ideas on other cases where each_cons would be
> useful? Or perhaps insight into why it's in Ruby?

You can find some uses in this mailing list's archive:

http://blade.nagaokaut.ac.jp/cgi-bin/vframe.rb?key=each_cons&cginame=namazu.rb&submit=Search&dbname=ruby-talk&max=50&whence=0

Useful applications are those where you need a moving window over a
collection of data, for example when calculating moving averages
(smoothing a plot) or distances between adjacent values.

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end