From: Dave Burt <dave@...>
Date: 2006-03-29T14:03:42+09:00
Subject: Re: How to interator over two arrays?

"brez! !!" asked:
> Let me start by saying I really like Ruby iterators - anyhow I've been
> taking every opportunity to use the single line syntax like:
>
> StopWord.find(:all).each{ |x| @stop_words << x.stopword }
>
> yea!
> ...
> #assumes equal size arrays!
> def dotproduct(doc, query)
>   @product = Array.new(doc.length)
>   @i = 0
>   doc.each do |term|
>       @product[@i] = term * query[@i]
>       @i += 1
>   end
>   return sum(@product)
> end
>
> Any thoughts on getting this into single-line syntax? Just curious.

Here ya go:

dotproduct = doc.zip(query).inject(0) {|sum, (d, q)| sum + d * q }

Cheers,
Dave