Ruby array of hash. group_by and modify in one line

Question

I have an array of hashes, something like

[ {:type=>\"Meat\", :name=>\"one\"}, 
  {:type=>\"Meat\", :name=>\"two\"}, 
  {:type=>\"Fruit\", :n         


        

Answer 1

Using ActiveSuport's Hash#transform_values:

array.group_by{ |h| h[:type] }.transform_values{ |hs| hs.map{ |h| h[:name] } }
#=> {"Meat"=>["one", "two"], "Fruit"=>["four"]}