From: 7stud -- <bbxx789_05ss@...>
Date: 2009-04-29T15:36:44+09:00
Subject: Re: Hash#map

Fredrik wrote:
> Is there any good reason why Hash#map does not give back a Hash (Ruby
> 1.8 but same in 1.9 as far as I know)? I often find myself writing
> these kind of things:
> 
> newhash = oldhash.inject({}) { |h,(k,v)| h[k] = some_operation(v); h }
> 
> but that doesn't look pretty at all in my opinion. I want to just
> write like this:
> 
> newhash = oldhash.map { |k,v| some_operation(v) }
> 

class Hash
  def hashbackmap
    result = {}

    self.each do |key, val|
      result[key] = yield val
    end

    result
  end
end

h = {
  "red" => 10,
  "blue" => 20,
  "green" => 30
}

p h.hashbackmap {|x| x*2}

--output:--
{"green"=>60, "blue"=>40, "red"=>20}

I HAVE A PATENT!!  My licensing fees are cheap: $10 mth.


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