Ruby array of hash. group_by and modify in one line

ruby-on-rails ruby hash enumerable

array.group_by{|h| h[:type]}.each{|_, v| v.replace(v.map{|h| h[:name]})}# => {"Meat"=>["one", "two"], "Fruit"=>["four"]}

Following steenslag's suggestion:

array.group_by{|h| h[:type]}.each{|_, v| v.map!{|h| h[:name]}}# => {"Meat"=>["one", "two"], "Fruit"=>["four"]}

ruby-on-rails ruby hash enumerable

In a single iteration over initial array:

arry.inject(Hash.new([])) { |h, a| h[a[:type]] += [a[:name]]; h }

ruby-on-rails ruby hash enumerable

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

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