From: Robert Klemme <shortcutter@...>
Date: 2005-08-29T18:10:19+09:00
Subject: Re: [Q] how to unflatten a flat-array

2005/8/29, SHIGETOMI, Takuhiko <tshiget1@gw.nsw.co.jp>:
> greetings, Robert. thank you, it does make sense to me.
> 
> > >> res=[]; 0.step(a.length - 1,2) {|i| res << [a[i],a[i+1]]}; res
> > => [[0, 1], [2, 3], [4, 5], [6, 7], [8, 9]]
> 
> i know that an yieldee is 100% passive to its yielder, but i often feel
> desire to let it fetch to the next/previous yielded object from inside
> the yieldee.
> 
> don't you know any cool way to do this in ruby?

No, not generally.  With arrays you can use #each_with_index and in
the general case of Enumerable you can use inject to access the last
element, along the lines

enum.inject  {|last, current| .... ; current}

Kind regards

robert