Python学习——使用json模块存储数据

Posted 2020-11-20 qilf

JSON( Javascript Object )格式

json.dump( )两个实参：1. 要存储的数据 2.可用于存储数据的文件对象

　　　如 with open(filename, ‘w‘) as f_obj:

　　　　　　json.dump(numbers, f_obj)

json.load( )加载文件中的信息，1个实参：要读取信息的文件对象

练习：使用json存储和读取用户信息

import json


def get_stored_username():
    filename = ‘username.json‘
    try:
        with open(filename) as f_obj:
            username = json.load(f_obj)
    except FileNotFoundError:
        return None
    else:
        return username


def get_new_username():
    username = input("What is your name? ")
    filename = ‘username.json‘
    with open(filename, ‘w‘) as f_obj:
        json.dump(username, f_obj)
    return username


def greet_user():
    username = get_stored_username()
    if username:
        print("Welcome back, " + username + "!")
    else:
        username = get_new_username()
        print("We will remember you when you come back, " + username + "!")


greet_user()