Python 存储数据

1. 使用 json.dump() 和 json.load()

import json

numbers = [2, 3, 5, 7, 11, 13]

filename = 'numbers.json'

with open(filename, 'w') as f_obj:
    json.dump(numbers, f_obj)

import json

filename = 'numbers.json'

with open(filename) as f_obj:
    numbers = json.load(f_obj)

print(numbers)

2. 保存和读取用户数据

import json

filename = 'username.json'


def remember_user():
    username_r = input("What is your name? ")
    with open(filename, 'w') as f_obj:
        json.dump(username_r, f_obj)
    print("We'll remember you when you come back, " + username_r + "!")


def greet_user():
    with open(filename) as f_obj:
        username_g = json.load(f_obj)
    return username_g


try:
    username = greet_user()
except FileNotFoundError:
    remember_user()
else:
    print("Welcome back, " + username + "!")

3. 重构

import json

filename = 'username.json'


def get_stored_username():
    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? ")
    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'll remember you when you come back, " + username + "!")

本文参考自 《Python 编程：从入门到实践》