项目练习

user = ['xuan','chen']
passed = ['159','564']
s1 = '''
'1).注册新用户'
'2).用户登录'
'3).注销用户'
'4).显示用户名'
'5).修改用户信息'
'6).退出系统(exit(0))'
'''
while 1:
    print(s1)
    choose = int(input('请输入选项：'))
    if choose == 1:
# print('注册新用户')
        newname = input('用户名')
        if newname in user:
            print('用户名已存在')
        else:
            user.append(newname)
            newpass = input('请输入新密码：')
            passed.append(newpass)
        print(f'添加新用户{newname}成功')
    elif choose == 2:
# print('用户登录')
        newnname = input('请输入用户名：')
        newnpass = input('请输入密码：')
        if newnname in user and passed :
            print('登陆成功')
        else:
            print('登陆失败')
    elif choose == 3:
# print('注销用户')
        newnname = input('请输入你需要删除的用户')
        if newnname in user:
            indexnewnname = user.index(newnname)
            user.remove(newnname)
            passed.pop(indexnewnname)
            print(f'注销用户成功')
        else:
            print('此用户不存在')
    elif choose == 4:
# print('显示用户信息')
        for i in range(len(user)):
            print(user[i],passed[i],sep='  --  ')
    elif choose == 5:
# print('修改')
        new = input('请输入你需要修改的用户：')
        if new in user  :
            indexnew = user.index(new)
            user[indexnew] = input('请输入你需要修改的用户名：')
            passed[indexnew] = input('请输入你需要修改的用户密码：')
            print('修改成功')
        else:
            print('此用户不存在')
            break
    elif choose == 6:
        print('退出系统(exit(0))')
        break

    else:
        print('输入有误，请输入1--6的整数值')