ruby - DRYing up these helper methods -

i've got 3 methods this:

def total_fat   total = 0   meal_foods = current_user.meal_foods   meal_foods.each |food|     total += food.fat   end   return total end  

one fat, carbs, , protein.

i'd dry up.

i've tried method , didn't seem work passing in 'macro' string.

def total_of(macro)   total = 0   meal_foods = current_user.meal_foods   meal_foods.each |food|     total += food.macro   end   return total  end   

how this?

def total_of(marcro)   current_user.meal_foods.map(&marcro).inject(:+) end 

this takes array(-like) collection of meal_foods , maps array of marcro value of meal_foods, , injects "+" between each of numbers. make sure pass argument symbol, e.g. total_of(:fat).