python-3.x - 我怎样才能让这些功能在我的菜单中工作

Question

我正在尝试创建一个程序来生成一个杂货清单，将易腐烂和不易腐烂的物品分开，打印出每个子类的小计，总税收总额和总总额，以及按需库存。我有下面的代码，但我无法让它正常工作......非常感谢任何和所有帮助。我对此仍然很陌生，并且正在努力学习。请温柔...

class Grocery_list():

    def __init__(self,name,price):
        """ Defines gorcery list item"""

        self.name = name.title()
        self.price = price

    def __str__(self):
        """ Returns formated item info """
        return f"\nItem: {self.name}" f"\nPrice: ${self.price}"


    def get_name(self):
        """ Displays Item Name """
        return f"Item name: {self.name}"

    def get_price(self):
        """ Display Item Price """
        return f"\nYour item cost is {self.price}"

    def is_perishable(self):
        """ Defines if item is perishable """
        raise NotImplementedError ('Not Implemented in Grocery_list')

    def __add__(self, other):
        self.price = self.price + other.price
        subtotal = self.price
        return "Subtotal: " + '$%.2f' % (subtotal)




class Perishable(Grocery_list):
    """ Defines if item is perishable """
    def __init__(self, name, price):
        Grocery_list.__init__(self, name, price)

    def is_perishable(self):
        """ Defines if item is perishable """
        perishable = input(f"\nIs your item perishable, yes or no: ")
        perishable = perishable.lower()
        if perishable == 'yes':
            return True, f"{self.name} = perishable."
        elif perishable == 'no':
            return False, f"{self.name} = non-perishable."
        else:
            print ("\nI'm sorry, I didn't recognize your response. Please try again.")

class Non_perishable(Grocery_list):
    """ Defines if item is non-perishable """
    def __init__(self, name, price):
        Grocery_list.__init__(self, name, price)

    def is_perishable(self):
        """ Defines if item is non perishable """
        perishable = input(f"\nIs your item perishable, yes or no: ")
        perishable = perishable.lower()
        if perishable == 'yes':
            return True, f"{self.name} = perishable."
        elif perishable == 'no':
            return False, f"{self.name} = non-perishable."
        else:
            print ("\nI'm sorry, I didn't recognize your response. Please try again.")

#=============================================================================    ================================
# Everything below this line is the issue.  I can't get the functions to work I need on function for each
# Menu item. (Adding items, Removing items, cart inventory, and getting a subtotal, tax amount, and total bill)

perishable = []
non_perishable = []


# This will work for the non_perishable list, but not the perishable.     Don't know why
def create_grocery_item():
    """ Create an Item for the grocery list """
    name = input("\nItem Name: ")
    price = input("\nItem Price: ")
    perishable = input("Is this item perishable, yes or no? ")
    perishable = perishable.lower()
    if perishable == 'yes':
        name = name.title()
        item = Perishable(name,price)
        perishable.append(item)
    elif perishable == 'no':
        name = name.title()
        item = Non_perishable(name,price)
        non_perishable.append(item)
    else:
        print ("Answer not recognized. Please try again.")

# I can't get this to work at all.
def remove_grocery_item():
    name = input("What item would you like to remove?")
    name = name.title()
    if name in perishable:
        del perishable [name]
        print (f"\nItem {name} has been removed from your cart")
    elif name in non_perishable:
        del non_perishable [name]
        print (f"\nItem {name} has been removed from your cart")
    else:
        print (f"\nI'm sorry, but {name} isn't in your cart. Please try again.")


# This one seems to work fine.
def print_cart():
    """ Print Items in Cart """
    print (f"The perishable items are: ")
    for item in perishable:
        print (f"Item:{item.name}" + f"/Price:${item.price}")
    print (f"\nThe non-perishable items are: ")
    for item in non_perishable:
        print (f"Item:{item.name}" + f"/Price:${item.price}")

# Honestly, I am not even sure where to start here....I can't figure out if I should create a seperate function
# for this, or if I should make a method inside the parent class. I'm supposed to have it add up the subtotal
# for each category (perishable and non_perishable), print those out seperately followed by the tax for and the
# overall bill total.

def check_out():
    sum = 0
    for item in perishable:
        sum += item
        print (sum)
    for item in non_perishable:
        sum += item
        print (sum)


# Here is the code for the menu options. This seems to work fine. I just need to figure out the functions
# to plug in....

ans=True
while ans:
    print("""
    1. Add item to cart
    2. Remove item from cart
    3. Show all items in cart
    4. Check out
    5. Exit
    """)

    ans = input("Please select an option from the list: ")
    if ans == '1':
        create_grocery_item()
    elif ans == '2':
        remove_grocery_item()
    elif ans == '3':
        print ("\nHere is your current cart: ")
        print_cart()
    elif ans == '4':
        print ("\nYour total bill is: ")
        check_out()
    elif ans == '5':
        print ("\nThank you for shopping with us. Goodbye!")
        ans = None
    else:
        print ("\nI'm sorry, that isn't a valid selection. Please try again")

标签： python-3.xclassoopuser-interfaceinheritance

Answer 1

您可能应该有一个class Item, 具有一个属性来判断一个Item是否易腐烂，以及一个GroceryList是 的集合的类item，配备适当的方法：

像这样的东西，也许：

[编辑]：

我为每个item类别添加了一个类，所以现在每个类别都有一个不同的type; 它们都继承自提供所有功能的基类。基类可以（但不是必须）继承自abc.ABC; IDK 如果允许你导入模块，所以我把它放在一边。
在实例化之外，其余代码保持不变，输出也是如此。

class AbstractItem:   
    def __init__(self, name, price):
        """ Defines gorcery list item"""
        self.name = name
        self.price = price

    def __str__(self):
        """ Returns formated item info """
        return f"Item: {self.name}, Price: ${self.price}"


class PerishableItem(AbstractItem):
    @property
    def perishable(self):
        return True


class NonPerishableItem(AbstractItem):
    @property
    def perishable(self):
        return False


class GroceryList:
    def __init__(self):
        self.items = []

    def add_item(self, item):
        self.items.append(item)

    def get_perishables(self):
        perishables = []
        for item in self.items:
            if item.perishable:
                perishables.append(item)
        return perishables

    def get_non_perishables(self):
        non_perishables = []
        for item in self.items:
            if not item.perishable:
                non_perishables.append(item)
        return non_perishables

    def __str__(self):
        res = ['Shopping List', '\n']
        res += ['\t', 'Perishables:\n']
        for item in self.get_perishables():
            res.append('\t\t' + str(item) + '\n')
        res += ['\t', 'Non Perishables:\n']
        for item in self.get_non_perishables():
            res.append('\t\t' + str(item) + '\n')
        return ''.join(res)


carrots = PerishableItem('Carrots', 12.5)
whiskey = NonPerishableItem('Whiskey', 45)
butter = PerishableItem('Butter', 22)

grocery = GroceryList()
grocery.add_item(carrots)
grocery.add_item(whiskey)
grocery.add_item(butter)

print(grocery)

输出：

Shopping List
    Perishables:
        Item: Carrots, Price: $12.5
        Item: Butter, Price: $22
    Non Perishables:
        Item: Whiskey, Price: $45