如何修复TypeError错误：list indices must be integers or slices, not str

你的代码存在几个关键错误： #

• 变量被错误覆盖：你一开始将price_and_name定义为存储糖果名称与价格的字典，但在while True循环内，把它重新赋值成了小写名称的列表，直接破坏了原本的字典结构。后续计算总价时，你试图用字符串索引列表，自然会触发类型错误——列表仅支持数字索引。
• 总价计算逻辑错误：计算总价时使用了+运算符，正确逻辑应该是价格乘以数量，需替换为*。
• 重复打印糖果列表：每次循环都会重新打印所有糖果，完全没必要，应将打印代码移到循环外部，仅在程序启动时打印一次。
• 冗余变量：定义了price_order列表但全程未使用，可直接删除。

修正后的完整代码 #

candy_name = ["Assorted Small Lollipops", "Assorted Flavours Small", "Assorted Flavours Large", "Large Lollipop", "100g Assorted Flavours Small", "100g Assorted Flavours Large", "Candy Cane", "100g Candy Canes"] # 所有糖果类型
candy_price = [0.1, 0.05, 0.2, 0.5, 4.5, 6, 0.2, 5.5] # 对应价格
total = 0
# 创建小写名称映射价格的字典，支持不区分大小写的用户输入
price_and_name = {name.lower(): price for name, price in zip(candy_name, candy_price)}
candy_order = []
number_order = []

# 仅打印一次可选糖果列表
for candies, price in zip(candy_name, candy_price):
    print(f"{candies} is ${price}")

while True:
    candy = input("What candy would you like to order? ").lower()

    while candy not in price_and_name:
        candy = input("That was not one of the options, check your spelling and try again. ").lower()
    candy_order.append(candy)
    
    number = input(f"How many {candy} would you like? ")
    while not number.isdigit() or int(number) <= 0:
        number = input("Only integers greater than 0 are allowed, please try again.")
    number_order.append(int(number))

    keep_ordering = input("Would you like to add more to your order? ").lower()
    while keep_ordering not in ["yes", "no"]:
        keep_ordering = input("Please enter just yes or no, try again. ").lower()

    if keep_ordering != "yes":
        for _candy, _number in zip(candy_order, number_order):
            total += price_and_name[_candy] * _number
        print(f"Your total is ${total:.2f}") # 保留两位小数，符合货币显示习惯
        break

核心修改点说明 #

1. 重构price_and_name为小写名称键的字典，既兼容不区分大小写的输入，又能直接通过名称获取对应价格。
2. 将糖果列表打印逻辑移至循环外，避免重复输出。
3. 修正总价计算的运算符为*，还原正确的金额计算逻辑。
4. 删除未使用的price_order变量，精简代码结构。
5. 改用f-string格式化输出，提升代码可读性。

内容的提问来源于stack exchange，提问作者tham thmit