db_path='db.txt'

def get_uname():

    while True:

        uname=input('请输入用户名：').strip()

        if uname.isalpha():

            with open(r'%s' %(db_path),'r',encoding='utf-8') as f:

                for i in f:

                    unifo=i.strip('\n').split(',')

                    print (unifo)   #查看查找过程

                    if uname==unifo[0]:

                        print('用户已存在，请重新输入')

                        break

                else:

                    return uname

        else:

            print ('用户名必须是中文或字母')

def get_pwd():

    while True:

        pwd1=input('请输入密码：').strip()

        pwd2=input('请再次输入密码：').strip()

        if pwd1 == pwd2:

            return pwd1

        else:

            print('两次输入的密码不一致，请重新输入...')

def get_bal():

    while True:

        bal=input('请输入余额：')

        if bal.isdecimal():

            return bal

        else:

            print ('钱是数字，傻逼 。。。')

def file_hanle(uname, pwd, bal):

     with open(r'%s' %(db_path),'a',encoding='utf-8') as f:

         f.write('%s,%s,%s\n' %(uname, pwd, bal))

def register():

    uname = get_uname()  # 拿到合法的用户名

    pwd = get_pwd()  # 拿到合法的密码

    bal = get_bal()  # 拿到合法的余额

    file_hanle(uname, pwd, bal)  # 写入文件

#===============================================装饰器

def example(func):

    def wrapper(*args,**kwargs):

        start_time = time.time()　　　　　　#可扩展功能

        res = func(*args, **kwargs)

        stop_time = time.time()

        print(stop_time - start_time)

        return res

    return wrapper

register=example(register)

#=====================================

res=register()

print (res)