From: "David A. Black" <dblack@...>
Date: 2008-12-01T04:29:44+09:00
Subject: Re: Help me understand how this block works?

Hi --

On Mon, 1 Dec 2008, Brian A. wrote:

> Thank you, that explains it very well for me.  Another quick question.
> Would it be possible to inject to two different vars?
>
> For instance if something like (syntax is probably wrong if its even
> possible):
>
> (5..10).inject(1).inject(2) {|product, variable_two, n| product *
> variable_two * n}

If the collection you're iterating through has pairs of values, you
can do this:

  [[1,2], [3,4], [5,6]].inject(0) {|acc, (x,y)| acc + x + y }

Kind of pointless here, since I'm just adding them up, but that
technique might help you.


David

-- 
Rails training from David A. Black and Ruby Power and Light:
INTRO TO RAILS (Jan 12-15) | ADVANCING WITH RAILS (Jan 19-22) *
Both in Fort Lauderdale, FL      * Co-taught with Patrick Ewing
See http://www.rubypal.com for details
Coming in 2009: The Well-Grounded Rubyist (http://manning.com/black2)