Python 中包含空列表的基本购物车

Question

我似乎无法使这个基本代码正常工作？我试图让人们从可用列表中的给定项目中进行选择，检查 userInput == available_items，将它们附加到我的空列表并允许用户继续、退出和打印他们的项目。感谢您的帮助！

available_items = ['Yogurt', 'Hummus', 'Bananas', 'Stawberries', 'Crackers', 'Veggie Pack', 'Shaving Cream', 'Razors', 'Deodorant' ]
userItems=[]
shopping_1st = True
while shopping_1st:
    userInput = input("Hello valued guest! Choose from the selection of available items to be added to your cart. ")
    response = input("'y' = Continue shopping?  'n' = continue to cart ")
    if str.lower(response) == 'n':
       shopping_1st = False
    elif str.upper(userInput) != available_items:
       print("Item not available:")
       print("Select from available items:")
    else:
        userItems.append(str.lower(userInput))
    for userInput in userItems:
        print(userInput)

Answer 1

您有多个问题：

str.upper(userInput) != available_items 将尝试将字符串与列表进行比较，这将始终 return False.
.upper 将所有字母转换为大写。考虑使用 .title().

尝试

...
elif userInput.title() not in available_items:
...

Answer 2

试试下面的代码：

available_items = ['Yogurt', 'Hummus', 'Bananas', 'Stawberries', 'Crackers', 'Veggie Pack', 'Shaving Cream', 'Razors', 'Deodorant' ]
userItems=[]
shopping_1st = True

while shopping_1st:
    userInput = input("Hello valued guest! Choose from the selection of available items to be added to your cart. ")

    if str.capitalize(userInput) not in available_items:
        print("Item not available:")
        print("Select from available items:")
    else:
        userItems.append(str.lower(userInput))

    response = input("'y' = Continue shopping?  'n' = continue to cart ")
    if str.lower(response) == 'n':
       shopping_1st = False       

for userInput in userItems:
    print(userInput)

Python 中包含空列表的基本购物车

Basic shopping cart with empty list in Python

python

for-loop

while-loop