Spring Boot+Mybatis设置sql日志打印-CFANZ编程社区

对于用户生成的数据，使用json保存它们大有裨益，因为如果不以某种方式进行存储，等程序停止运行时用户的信息将丢失。下面来看一个这样的例子：用户首次运行程序时被提示输入自己的名字，这样再次运行程序时就记住他了。我们先来存储用户的名字： remember_me.py

感谢大家的支持！欢迎订阅收藏！专栏将持续更新！

10.3.9 决定报告哪些错误

10.4 存储数据

注意 JSON（JavaScript Object Notation）格式最初是为JavaScript开发的，但随后成了一种常见格式，被包括Python在内的众多语言采用。

10.4.1 使用 json.dump()和 json.load()

import json
numbers = [2, 3, 5, 7, 11, 13]
1 filename = 'numbers.json'
2 with open(filename, 'w') as f_obj:
3 json.dump(numbers, f_obj)

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

mport json
1 filename = 'numbers.json'
2 with open(filename) as f_obj:
3 numbers = json.load(f_obj)
print(numbers)

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

10.4.2 保存和读取用户生成的数据

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

What is your name? Eric
We'll remember you when you come back, Eric!

import json
filename = 'username.json'
with open(filename) as f_obj:
1 username = json.load(f_obj)
2 print("Welcome back, " + username + "!")

Welcome back, Eric!

import json
# 如果以前存储了用户名，就加载它
# 否则，就提示用户输入用户名并存储它
filename = 'username.json'
try:
1 with open(filename) as f_obj:
2 username = json.load(f_obj)
3 except FileNotFoundError:
4 username = input("What is your name? ")
5 with open(filename, 'w') as f_obj:
 json.dump(username, f_obj)
 print("We'll remember you when you come back, " + username + "!")
else:
 print("Welcome back, " + username + "!")

What is your name? Eric
We'll remember you when you come back, Eric!

Welcome back, Eric!

10.4.3 重构

import json
def greet_user():
1 """问候用户，并指出其名字"""
filename = 'username.json'
try
 with open(filename) as f_obj:
 username = json.load(f_obj)
 except FileNotFoundError:
 username = input("What is your name? ")
 with open(filename, 'w') as f_obj:
 json.dump(username, f_obj)
 print("We'll remember you when you come back, " + username + "!")
 else:
 print("Welcome back, " + username + "!")
greet_user()

import json
def get_stored_username():
1 """如果存储了用户名，就获取它"""
filename = 'username.json'
try:
 with open(filename) as f_obj:
 username = json.load(f_obj)
 except FileNotFoundError:
2 return None
 else:
 return username
def greet_user():
 """问候用户，并指出其名字"""
 username = get_stored_username()
3 if username:
 print("Welcome back, " + username + "!")
 else:
 username = input("What is your name? ")
 filename = 'username.json'
 with open(filename, 'w') as f_obj:
 json.dump(username, f_obj)
 print("We'll remember you when you come back, " + username + "!")
greet_user()

import json
def get_stored_username():
 """如果存储了用户名，就获取它"""
 --snip--
def get_new_username():
 """提示用户输入用户名"""
 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():
 """问候用户，并指出其名字"""
 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 + "!")
greet_user()

关于“Python”的核心知识点整理大全25-CSDN博客

关于“Python”的核心知识点整理大全12-CSDN博客