Python之简单的用户登录和注册

#!/bin/bash/env python
# -*- coding:utf-8 -*-

def login(username,password):
    """
    用于用户名密码的登录
    :param username: 用户名
    :param password:  密码
    :return:  True，用户验证成功；False，验证失败
    """
    with open('cai.log','r',encoding="utf-8") as f:
        for line in f:      #一行一行的读取
            line = line.strip()     #去除两端的空格及换行符
            line_list = line.split("$")     #以$符号进行分割
            if username == line_list[0] and password == line_list[1]:
                return True
    return False

def register(username,password):
    """
    注册用户
    :param username: 用户名
    :param password: 密码
    :return: True，注册成功
    """
    with open('cai.log',"a",encoding="utf-8") as f:
        temp = "n" + username + "$" +password
        f.write(temp)
    return True

def user_exist(username):
    """
    检查用户是否已经存在
    :param username: 用户名
    :return: True，则用户名已经存在；False，用户名不存在
    """
    with open('cai.log',"r",encoding="utf-8") as f:
        for line in f:
            line = line.strip()
            line_list = line.split("$")
            if username == line_list[0]:
                return True
    return False

def main():
    print("欢迎登陆瑞的系统")
    inp = input("1: 登陆;2: 注册")

    user = input("请输入用户名：")
    pwd = input("请输入密码：")

    if inp == "1":
        is_login = login(user,pwd)
        if is_login:
            print("登录成功")
        else:
            print("登录失败")
    elif inp == "2":
        is_exist = user_exist(user)
        if is_exist:
            print("用户已经存在，无法注册")
        else:
            result = register(user,pwd)
            if result:
                print("注册成功")
            else:
                print("注册失败")

main()