From: "David A. Black" <dblack@...>
Date: 2005-08-29T20:51:50+09:00
Subject: Re: [Q] how to unflatten a flat-array

Hi --

On Mon, 29 Aug 2005, SHIGETOMI, Takuhiko wrote:

> greetings, Daniel. true. 'next' works.
>
>> You can't easily go backwards, but skipping to the next is
>> as easy as saying `next'.
>
> on the other hand, and as your reference 'cannot easyily go backwards',
> 'next' forgets current object unless any variable on outside of the
> yieldee block.
>
> how about writing a special yielder like as below ..
>
>    any-enumerable-object.sliding_each do |prev,this,next|
>      ...
>    end
>
> - could be really useful?
> - any other good name?

This might help you on this:

irb(main):003:0> require 'enumerator' 
=> true
irb(main):004:0> [1,2,3,4,5,6].each_cons(2) {|x| p x }
[1, 2]
[2, 3]
[3, 4]
[4, 5]
[5, 6]
=> nil
irb(main):005:0> [1,2,3,4,5,6].each_cons(3) {|x| p x }
[1, 2, 3]
[2, 3, 4]
[3, 4, 5]
[4, 5, 6]


David

-- 
David A. Black
dblack@wobblini.net