From: Robert Dober <robert.dober@...>
Date: 2009-07-29T21:12:52+09:00
Subject: Re: previous value in array block

On Wed, Jul 29, 2009 at 12:56 PM, David A. Black<dblack@rubypal.com> wrote:
> 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 }
A beauty, sorry did not see it before my post!
Cheers
Robert