Reverse a hash in Ruby

Question

How would I reverse the elements in the hash, keeping the same values and keys, but reversing their order in the hash.

Like so:

{ \"4\" => \"happiness         


        

Answer 1

You could convert the Hash to an Array, reverse that, and then convert it back to a Hash:

reversed_h = Hash[h.to_a.reverse]

Hash#to_a gives you an array of arrays, the inner arrays are simple [key,value] pairs, then you reverse that array using Array#reverse, and Hash[] converts the [key,value] pairs back into a Hash.

Ruby 2.1 adds an Array#to_h method so you can now say:

reversed_h = h.to_a.reverse.to_h