From: "David A. Black" <dblack@...>
Date: 2009-07-29T19:56:34+09:00
Subject: Re: previous value in array block

Hi --

On Wed, 29 Jul 2009, Xavier Noria wrote:

> each_cons seems natural here:
>
> require 'enumerator'
>
> a = [1, 3, 3, 2]
> b = a[0, 1]
>
> a.each_cons(2) { |x, y| b << y - x }

Here's a 1.9 way, probably guilty of gross wasteage (by creating an
extra new array) but kind of cool:

[0,*a].each_cons(2).map {|x,y| y - x }


David

-- 
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