cars.each do |car|
#ensure containers exist
sorted_cars[car.make] ||= {}
sorted_cars[car.make][car.model] ||= {}
sorted_cars[car.make][car.model][car.year] ||= []
#put the car in its place
sorted_cars[car.make][car.model][car.year] << car
end
sorted_cars
end
end
Vehicle.all_sorted[‘honda’][‘civic’][1996] #=> Array of cars