10-11 喜欢的数字

1. 项目

编写一个程序，提示用户输入他喜欢的数字，并使用json.dump()将这个数字存储到文件中。再编写一个程序，从文件中读取这个值，并打印消息“I know your favorite number! It’s _____.”。

 

2. 代码

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import json   def get_favorite_number():     """如果存储了喜欢的数字，就获取它"""     filename = 'favorite_number.json'     try:         with open(filename) as f_obj:             favorite_number = json.load(f_obj)     except FileNotFoundError:         return None     else:         return favorite_number   def get_new_number():     """提示用户输入喜欢的数字"""     favorite_number = input("What's your favorite number? ")     filename = 'favorite_number.json'     with open(filename, 'w') as f_obj:         json.dump(favorite_number, f_obj)     return favorite_number     def read_number():     """读取喜欢的数字，并打印一段话"""     favorite_number = get_favorite_number()     if favorite_number:         print("I know your favorite number! It's " + favorite_number + " .")     else:         favorite_number = get_new_number()         print("I know your favorite number! It's " + favorite_number + " .")   read_number()

　　

3. 执行结果

没有favorite_number.json文件就创建一个。如果有就直接打印结果。