retrieve_keys

[1] pry(main)> hash = {a: 1, b: 2, c: 3}
=> {:a=>1, :b=>2, :c=>3}
[2] pry(main)> class Hash
[2] pry(main)*   def retrieve_keys(*keys)
[2] pry(main)*     self.reduce({}) { |h, (k, v)|
[2] pry(main)*       keys.include?(k) ? h.merge!({k => v}) : h
[2] pry(main)*     }  
[2] pry(main)*   end  
[2] pry(main)* end  
=> nil
[3] pry(main)> hash.retrieve_keys(:a, :b)
=> {:a=>1, :b=>2}