From: Michael Garriss <mgarriss@...>
Date: 2003-09-18T08:27:08+09:00
Subject: Re: going over two interators

Michael Garriss wrote:

> I often find that I need to go over two enumerables in parallel.  I 
> have used a little method called 'both' for this:
>
> irb
> arr1 = [1,2,3,4,5]
> --> [1, 2, 3, 4, 5]
> arr2 = [6,7,8,9,10]
> --> [6, 7, 8, 9, 10]
> def both( enum1, enum2 )
>  enumC = enum2.dup
>  enum1.each do |e1|
>    yield e1, enumC.shift
>  end
> end
> --> nil
> both( arr1, arr2 ) do |a,b|
>  puts "#{a} : #{b}"
> end
> 1 : 6
> 2 : 7
> 3 : 8
> 4 : 9
> 5 : 10
> --> [1, 2, 3, 4, 5]
>
>
> It assumes that enum1 is at least at big as enum2.
>
> Is there a way someone can think of that's more efficient then this?  
> Namely getting rid of the 'dup'.  Or maybe I'm missing some rubyism 
> that would make this easier.
>

I just realized that a) my spell checker doesn't look at the subject 
line, and that b) this only works for arrays.  How could I make it work 
(well) for any enumerable?

Michael