From: Trans <transfire@...>
Date: 2008-11-18T21:39:52+09:00
Subject: Re: function to select only certain key/value pairs from hash?



On Nov 18, 3:31 am, Luc Heinrich <l...@honk-honk.com> wrote:
> On 17 nov. 08, at 23:50, Aryk Grosz wrote:
>
> > hash.from_keys(:a,:b) => {:a=> 1, :b=> 2}
>
> I tried to resist making this a one-liner and went for the clean and  
> explicit way :)
>
> class Hash
>      def from_keys(*keys)
>          selected_values = self.values_at(*keys)
>          selected_key_values = keys.zip(selected_values)
>          Hash[*selected_key_values.flatten]
>      end
> end
>
> hash = {:a => 1, :b => 2, :c => 3}
> p hash.from_keys(:a, :b)
>
> => {:a=>1, :b=>2}

require 'facets/hash/slice'

T.