python - 类型错误 : 'Food' object does not support indexing

Question

self.food_list = [['apple', 100, 'Fruit', 384.0], ['orange', 100, 'Fruit', 384.0]]

我想对索引 3 中的元素求和。预期输出为所有食物的总热量为 768.0Kcal

def totalCalorie(self):
    for i in range(0, len(self.food_list)):
        j = self.food_list[i][3]
        j += j
    print("Total calorie of all food is {}Kcal".format(j))

但是出现了以下错误:

Traceback (most recent call last):
  File "D:/PythonTim/Assignment/nutritionDriver.py", line 60, in <module> 
    main()
  File "D:/PythonTim/Assignment/nutritionDriver.py", line 43, in main
    patient.totalCalorie()
  File "D:\PythonTim\Assignment\nutritionApp.py", line 132, in totalCalorie
    j = self.food_list[i][3]
TypeError: 'Food' object does not support indexing

我想做的是，当用户想要合计列表中的所有卡路里时，系统将显示列表中的总卡路里。

还有其他方法吗？谢谢!

编辑:

class Food:
    def __init__(self, name, quantity, category, calorie):
        self.name = name
        self.quantity = quantity
        self.category = category
        self.calorie = calorie

class FoodList:

    def __init__(self):
        self.food_list = []

    def totalCalorie(self):
        j=0
        for i in self.food_list:
            j += i[3]
        print("Total calorie of all food is {}Kcal".format(j))

    def addFood(self, newfruit):
        self.food_list.append(newfruit)

name = input("Name? ")
quantity = input("Quantity? ")
category = input("Category? ")
calorie = input("Calorie? ")
f = Food(name, quantity, category, calorie)
patient = FoodList()
patient.addFood(f)

name1 = input("Name? ")
quantity1 = input("Quantity? ")
category1 = input("Category? ")
calorie1 = input("Calorie? ")
f1 = Food(name1, quantity1, category1, calorie1)
patient.addFood(f1)

patient.totalCalorie()

Answer 1

只需迭代 food_list 的元素即可。作为对罗宾爵士答案的改进:

class Food:
    food_list = []

    def totalCalorie(self):
        j=0
        for i in self.food_list:
            j += i[3]
        print("Total calorie of all food is {}Kcal".format(j))

    def addFood(self,newfruit):
        self.food_list.append(newfruit)


f = Food()
f.addFood(['banana', 100, 'Fruit', 100.0])
f.addFood(['orange', 100, 'Fruit', 384.0])
f.totalCalorie()

我也编辑了 j += 部分，以便它也适用于 2 个以上的元素。