From: Robert Klemme <shortcutter@...>
Date: 2006-03-07T06:54:08+09:00
Subject: Re: What is the best way to iterate through two containers of the same length?

2006/3/6, Mark  Watson <mark.watson@gmail.com>:
> If I have two containers c1 and c2 of the same length, what is the
> proper "Ruby way" to do this:
>
> c1.length.times {|i|
>   # access c1[i], c2[i]
> }
>
> I like that Ruby container classes provide their own iterators, but
> what I would like to have is something like:
>
> (c1,c2).each {|x1,x2| .... }
>
> I thought of writing my own iterator class so that I could do something
> like:
>
> Iterator.new(c1,c2).each {|x1,x2| .... }
>
> but that looks clumsy and inefficient.
>
> I am transitioning to using mostly Ruby (moving away from Java, Lisp,
> and Smalltalk) and I would like to use the proper Ruby idioms.

If the two are arrays you can use Array#zip:

>> %w{foo bar baz}.zip([1,2,3]) {|a,b| print a, "-", b,"\n"}
foo-1
bar-2
baz-3

For the more general case you can look at Generator
http://ruby-doc.org/stdlib/libdoc/generator/rdoc/

Kind regards

robert

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