Python3学习实例上手（1）-----登录认证

要求：输入用户名、密码进行认证，认证成功则欢迎，若输错三次会锁定最后一次输入的用户

知识点归纳：字典操作（items()方法）、字符串操作（如strip()、split()等）、文件读写（for line in f 变迭代器）、while&else循环、if判断

其他：分清变量类型，不要混淆整数和字符串数据类型

源码：

# -*- coding:utf-8 -*-
# Author: WUJiang

# 分别存储用户密码、用户锁定标志
info_pw = {}
info_lock = {}
# 读取txt中记录并对上述变量赋值
with open("user_info.txt", "r") as f:
    for line in f:
        line = line.strip()
        name = line.split(" ")[0]
        pw = line.split(" ")[1]
        lock_flag = line.split(" ")[2]
        info_pw[name] = pw
        info_lock[name] = lock_flag

# -------------用户登录-------------------
login_num = 0
while login_num < 3:
    login_name = input("enter your name:")
    login_pw = input("enter your password:")
    if login_name in info_pw.keys():
        if info_lock[login_name] == "0":  # 易遗漏""
            if info_pw[login_name] == login_pw:
                print("welcome %s log in" % login_name)
                break
            else:
                print("wrong password")
        else:
            print("user has been locked, please contact to admin")
            break
    else:
        print("user does not exist")
    login_num += 1
else:
    print("input num is out of limit")
    print("%s is locked" % login_name)
    info_lock[login_name] = "1"  # 被这里坑惨了！！！易遗漏""!!!
    # ----若锁定标志更新，需将更新数据写回txt--------
    with open("user_info.txt", "w") as f:
        for i, j in info_pw.items():
            data = i + " " + j + " " + info_lock[i] + "\n"
            f.write(data)