Question

我正在尝试一项作业，在该作业中，我需要设置带有列表的嵌套字典。用户需要输入类别并查看类别中的可用书籍，并查看每本书的价格。

    # List of Books
    Category = {
        "Fiction": {
        "Rapunzel": 3.00,
        "Cindrella": 4.00
        },
        "Non-Fiction": {
        "Life of Khans": 7.00,
        "History of Rome": 18.00
        },
        "Manga": {
        "Naruto": 2.00,
        "Attack on Titan": 3.00
        }
   }


   def enquiry_system():
       print("Welcome to Alice Bookstore\n")
       print("These are the available categories:\n")
       for item in Category:
           print(item)

       user_category = input("\nPlease select a category to view the list 
                              of books: ")
       if user_category in Category:
           print(f"\nBook Title: {', '.join(Category[user_category])}")
       user_book = input("\nPlease select your choice of the book: ")
           if user_book in Category[user_category]:
              price = user_category[user_book]
              print(f'\n The price is:{price}')

现在在代码的最后一行，我如何查看这本书的价格？我不知道如何在嵌套字典的列表中获取键的值。

我得到的错误是：

    Traceback (most recent call last):
        File "D:/Python/OOP/Main.py", line 33, in <module>
          enquiry_system()
        File "D:/Python/OOP/Main.py", line 30, in enquiry_system
          print(Category[user_category[user_book]])
    TypeError: string indices must be integers

Answer 1

在倒数第二行上，您正在查找字符串中的索引，而不是在其上执行if语句的字典。

  price = Category[user_category][user_book]

Answer 2

user_category只是用户输入的任何字符串。要获取价格数据，您必须引用字典类别。这是示例代码：

price = Category[user_category][user_book]

获取嵌套字典中列表的值

2 个答案: