用户注册

一、需求

1、新建一个txt，写入部分用户名、密码

2、读取txt，判断用户是否存在，存在则提示存在

3、新注册的用户，写入txt

二、实现代码

with open('users.txt', 'r', encoding='utf-8') as f:
    users = []
    for line in f.readlines():
        line = line.strip('\n')  # 去掉换行符\n
        b = line.split(',')  # 将每一行以逗号为分隔符转换成列表
        users.append(b)
dic = dict(users)    #将list转为字典
print(dic)
while True:
    username = input('username:').strip()
    pwd = input('password:').strip()
    cpwd = input('password:').strip()
    if username == '' and pwd =='' and cpwd =='':
        print('用户名或密码不能为空')
    elif username in dic:
        print('用户已存在')
    elif pwd !=cpwd:
        print('两次密码输入不一致')
    else:
        print('欢迎{}注册'.format(username))
        with open('users.txt', 'a', encoding='utf-8') as f1:
            f1.write(username+','+pwd +'\n')
            f1.close()