From: "David A. Black" <dblack@...>
Date: 2009-08-30T00:14:33+09:00
Subject: Re: #map, #select semantics

Hi --

On Sat, 29 Aug 2009, Yukihiro Matsumoto wrote:

> Hi,
>
> In message "Re: #map, #select semantics"
>    on Sat, 29 Aug 2009 21:32:21 +0900, 7rans <transfire@gmail.com> writes:
>
> |Let's say we have
> |
> |  [[:a,1], [:b,2]].map{ |(k,v)| [k, v+1] }  #=> [[:a,2], [:b,3]]
> |
> |We might have something like:
> |
> |  [[:a,1], [:b,2]].using({}).map{ |(k,v)| [k, v+1] }  #=> {:a=>2, :b=>3}
>
> [[:a,1], [:b,2]].inject({}){|h,(k,v)| h[k]=v+1; h}     #=> {:a=>2, :b=>3}

Or (at least in 1.9):

   [[:a,1], [:b,2]].each_with_object({}){|(k,v),h| h[k]=v+1 }


David

-- 
David A. Black / Ruby Power and Light, LLC / http://www.rubypal.com
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