Question

class Item:
    def __init__(self, code, desc, price, quantity):
        self.__code = code             # the item code
        self.__description = desc      # the item description
        self.__price = price           # the item unit price
        self.__quantity = quantity     # the number of item available

    def getCode(self):
        return self.__code

    def setCode(self, code):
        self.__code = code;

    def getDescription(self):
        return self.__description

    def setDescription(self, desc):
        self.__description = desc

    def getPrice(self):
        return self.__price

    def setPrice(self, price):
        self.__price = price

    def getQuantity(self):
        return self.__quantity

    def setQuantity(self, quantity):
        self.__quantity = quantity

    def __repr__(self):
        return 'Item({0}, {1}, {2}, {3})'.format(self.__code, self.__description, self.__price, self.__quantity)    

    def __str__(self):
        return '{0}, {1}, {2}, {3}'.format(self.__code, self.__description, str(self.__price), str(self.__quantity))

# This function displays all the items on sale.
    def display_items(self):
        for i in range(len(self.__items)):
            if self.__items[i]
            print(self.__items[i])

BC001, Fresh toast bread white (700g), 3.99, 20 
BC002, Low-fat milk (2 liter), 4.8, 10 
BC003, V-energy drink, 2.75, 10 
BC005, Coca-Cola (300 ml), 2.5, 10 
BC006, Pineapple, 3.6, 6 
BC007, Mango, 1.89, 4 
BC008, Snickers chocolate bar, 1.8, 20 
BC009, Broccoli, 1.47, 11 
BC010, Washed Potato (2.5kg), 2.98, 7 
BC011, Good-morning cereal, 5.6, 10 
BC012, Rose apple (1.5kg bag), 4.98, 5 
BC013, Avocado (4pk), 4.99, 5 
BC014, Bananas (850g bag), 2.96, 4 
BC015, Kiwi fruit green (1kg), 2.45, 10 
BC016, Rock melon, 7.98, 2 
BC017, Lettuce, 2.99, 12 
BC018, Chocolate block (200g), 3.59, 10 
BC020, Parsley curly, 1.99, 6 
BC021, Grapefruit 1kg, 3.99, 7

请注意，您只应显示数量值大于零的商品。也就是说，如果某个商品缺货（其数量值为0），则不应将其列为待售商品。例如，在上面的输出中，未显示项目'BC004，新鲜大蒜（450g）'。

Answer 1

您想要创建一个类变量和一个类方法：

class Item:

    instances = []

    @classmethod
    def display_all(cls):
        for item in cls.instances:
            if item.getQuantity() > 0:
                print(item)

    def __init__(self, code, desc, price, quantity):
        Item.instances.append(self)
        ...

    ...

我不明白如何编写display_items fucntion

1 个答案: