Question

因此，在编写一些代码来计算购物清单总数时，我编写了这段代码（在Codecademy上）：

    shopping_list = ["banana", "orange", "apple"]

stock = {
    "banana": 6,
    "apple": 0,
    "orange": 32,
    "pear": 15
}

prices = {
    "banana": 4,
    "apple": 2,
    "orange": 1.5,
    "pear": 3
}

# Write your code below!
def compute_bill(food):
    total = 0
    for item in food:
        if stock[item] > 0:
            total = total + prices[item]
            value = stock[item] - 1
            return value
    return total

现在，当我运行它时，它没有给出错误，但它说当1个梨，苹果和香蕉在购物清单上而不是'7'时它给出答案'5'。我查看了代码，但找不到我错的地方。

Answer 1

只需从for循环中删除return value：

def compute_bill(food):
    total = 0
    for item in food:
        if stock[item] > 0:
            total += prices[item]
            #remove item from stock 
            stock[item] -= 1
    return total

请注意，根据输入数据，库存中没有苹果。因此，只能从购物清单中购买一个香蕉和一个橙子，总价格为5.5：

print compute_bill(shopping_list)
5.5
stock : {'orange': 31, 
         'pear': 15, 
         'banana': 5, 
         'apple': 0}

'for'循环出了什么问题？

1 个答案: