Needed ingredients for recipes Before making a dish, we want to check whether we already have the necessary ingredients in our pantry or whether we need to go shopping. For this problem, you will implement a method needed_ingredients for the Pantry class. needed_ingredients takes a list of recipes as its argument and returns a new Pantry containing everything missing from our pantry to make all the recipes in the list. If our pantry already has all the necessary ingredients in the needed quantities, needed_ingredients returns an empty Pantry. There may be repeated recipes in the input list, and the input list may be empty. # You may wish to use defaultdict to implement needed_ingredients. from collections import defaultdict def needed_ingredients (self, recipes) : "Given a list of recipes, computes which ingredients to buy, and in which quantity, to be able to make all recipes. Can be implemented in 10 lines of code."* * #Code here raise Not ImplementedError ()

See explaination

Explanation:

class Pantry (AD):

def __init__ (self, ingredients):

""" We initialize the Pantry class by passing the ingredients that were passed

in to the initializer for the superclass AD"""

super ().__init__ (ingredients)

def needed_ingredients (self, recipes):

""" Given a list of recipes, computes which ingredients to buy, and in which

quantity to be able to make all recipes. Can be implemented in 10 lines of code."""

# define the object new_pantry to contain the ingredients needed

new_pantry = Pantry ({})

ingredients_present = self

# loop over the recipes in the list

for recipe in recipes:

# convert ingredients of recipe from AD to Pantry

ingredients = Pantry (recipe. ingredients)

# subtract the recipe's ingredients from ingredients_present

ingredients_present = ingredients_present - ingredients

# loop over the ingredients_present

for key in ingredients_present:

# if any ingredients's quantity < 0, add it to new_pantry

if ingredients_present[key] < 0:

# check if ingredient is present in new_pantry, add the quantity to existing quantity

if key in new_pantry:

new_pantry[key] + = - 1 * (ingredients_present[key])

else: # if ingredient is not present in new_pantry, make a new entry for the ingredient

new_pantry[key] = - 1 * (ingredients_present[key])

ingredients_present[key] = 0 # set the quantity of the ingredient in ingredients_present to 0

return new_pantry