Ruby, turn array of hashes into single hash

Question

I have the following Array of Hashes:

a = [{:a => 1, :b => "x"}, {:a => 2, :b => "y"}]

I need to turn it into:

z={"x" => 1, "y" => 2}

or:

z={1 => "x", 2 => "y"}

Can I do this in a clean and functional way?

rainkinz · Accepted Answer · 2013-07-08 23:15:07Z

2

Something like this:

Hash[a.map(&:values)] # => {1=>"x", 2=>"y"}

if you want the other way:

Hash[a.map(&:values).map(&:reverse)] # => {"x"=>1, "y"=>2}

incorporating the suggestion from @squiguy:

Hash[a.map(&:values)].invert

answered Jul 8, 2013 at 22:50

rainkinz

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1 Comment

You can just use invert for the bottom example, since it will handle duplicate keys, but +1.