Addition for hashes in Ruby

peter (Peter Cooperx) — Mon, 20 Feb 2006 08:48:52 GMT

Why, oh, why is there no addition for hashes in Ruby? 'update' can do the trick, but only returns what was updated, rather than the whole updated hash. It also forces an update rather than being passive.

Sometimes you only want to temporarily do an add, and this is how I pulled it off:

class Hash

  def +(add)

    temp = {}

    add.each{|k,v| temp[k] = v}

    self.each{|k,v| temp[k] = v}

    temp

  end

end

Now you can do stuff like:

x = { :a => 1 }

y = { :b => 2 }



# x + y => { :a => 1, :b => 2 }, but x and y are untouched

# x + { :c => 3 } => { :a => 1, :c => 3 }

If you want to force an add, it's easy:

x += y => { :a => 1, :b => 2 } (this is now what x contains)

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Addition for hashes in Ruby