From: Fredrik <fredjoha@...>
Date: 2009-04-29T15:00:03+09:00
Subject: Hash#map

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) }

I finally got around to change this behaviour for my own code, but are
all Ruby users supposed to invent this wheel on their own? Wouldn't it
be better if Hash#map behaved like this? Or is there something I am
missing?

class Hash
  def hashmap
    self.inject({}) do |newhash, (k,v)|
      newhash[k] = yield(k, v)
      newhash
    end
  end
end


Regards,
Fredrik