From: Paul Brannan <pbrannan@...>
Date: 2001-10-06T02:46:36+09:00
Subject: [ruby-talk:22133] Re: Possible to iterate on two enumerables together?

On Sat, 6 Oct 2001, Phil Mitchell wrote:

> If I have two enumerables, is there a ruby way to connect them? That
> is, I want to march through the two collections and operate on pairs
> of items. The best I came up with was to convert each one to an array
> and then iterate on the index.

Yes, this is possible using a number of methods:
1) Convert the two enumerables to arrays using to_a, each, or collect,
   then iterator over the arrays using the [] operator and an index.
2) Use some other form of random-access to "iterate" through each
   enumerable.
3) Use a continuation to "continue" iteration through each enumerable.

Obviously not all methods are optimal for all enumerables.

Anyone know of other options?

See the discussion at http://www.rubygarden.org/article.php?sid=109
regarding knu's Generator, which does exactly what you want (using
continuations).

Paul