From: "David A. Black" <dblack@...>
Date: 2009-07-29T21:16:24+09:00
Subject: Re: previous value in array block

Hi --

On Wed, 29 Jul 2009, Robert Dober wrote:

> On Wed, Jul 29, 2009 at 10:50 AM, Xavier Noria<fxn@hashref.com> 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 }
> and purely functional
> ( [0] + a ).each_cons( 2 ).map{ |x,y| y -x }
> or with Tom's map arity trick implemented
> ( [0] + a ).map{ | x, y | y - x }

I don't understand that last one. Is this some kind of override of map
that turns it into each_cons + map?


David

-- 
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