From: Drew Olson <olsonas@...>
Date: 2007-07-20T02:19:29+09:00
Subject: Re: Map more than one array at once

Wil wrote:
> Hi all,
> 
> I've been using Ruby for a while now, and have enjoyed it immensely.
> However, I haven't yet found how to map more than one array at once.
> The common example is calculating the dot product.

Here's an example using inject, no need for a temp variable:

irb(main):001:0> def dot_prod a,b
irb(main):002:1>   a.zip(b).inject(0) do |dp,(a,b)|
irb(main):003:2*     dp + a*b
irb(main):004:2>   end
irb(main):005:1> end
=> nil
irb(main):006:0> dot_prod([1,2,3],[4,5,6])
=> 32


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