continue语句、while循环

编写登陆接口

输入用户名密码

认证成功后显示欢迎信息

错误三次后锁定

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午8:57

_user = "smoke"
_passwd = "smoke520"

for i in range(3):
    username = input("Username:")
    password = input("Password:")

    if username == _user and password == _passwd:
        print("Welcome %s login..." % _user)
        break   #跳出，中断
    else:
        print("Invalid username or password!")

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login.py
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!

Process finished with exit code 0

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午8:57

_user = "smoke"
_passwd = "smoke520"

for i in range(3):
    username = input("Username:")
    password = input("Password:")

    if username == _user and password == _passwd:
        print("Welcome %s login..." % _user)
        break   #跳出，中断
    else:
        print("Invalid username or password!")

print("要不要脸，愁流氓。")

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login.py
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
要不要脸，愁流氓。

Process finished with exit code 0

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午8:57

_user = "smoke"
_passwd = "smoke520"

for i in range(3):
    username = input("Username:")
    password = input("Password:")

    if username == _user and password == _passwd:
        print("Welcome %s login..." % _user)
        break   #跳出，中断
    else:
        print("Invalid username or password!")

print("要不要脸，愁流氓。")

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login.py
Username:smoke
Password:smoke520
Welcome smoke login...
要不要脸，愁流氓。    #登陆成功也打印

Process finished with exit code 0

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午8:57

_user = "smoke"
_passwd = "smoke520"

passwd_authentication = False    #假，不成立，flag标志位

for i in range(3):
    username = input("Username:")
    password = input("Password:")

    if username == _user and password == _passwd:
        print("Welcome %s login..." % _user)
        passwd_authentication = True    #成立
        break   #跳出，中断
    else:
        print("Invalid username or password!")

if not passwd_authentication:   #只有在True的情况下，条件成立
    print("要不要脸，愁流氓。")

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login.py
Username:smoke1
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke520
Welcome smoke login...

Process finished with exit code 0

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午8:57

_user = "smoke"
_passwd = "smoke520"

passwd_authentication = False    #假，不成立

for i in range(3):
    username = input("Username:")
    password = input("Password:")

    if username == _user and password == _passwd:
        print("Welcome %s login..." % _user)
        passwd_authentication = True    #成立
        break   #跳出，中断
    else:
        print("Invalid username or password!")

if not passwd_authentication:   #只有在True的情况下，条件成立
    print("要不要脸，愁流氓。")

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login.py
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
要不要脸，愁流氓。

Process finished with exit code 0

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午8:57

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午8:57

_user = "smoke"
_passwd = "smoke520"

for i in range(3):
    username = input("Username:")
    password = input("Password:")

    if username == _user and password == _passwd:
        print("Welcome %s login..." % _user)
        break   #跳出，中断
    else:
        print("Invalid username or password!")
else:
    print("要不要脸，愁流氓。")


/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login.py
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke520
Welcome smoke login...

Process finished with exit code 0

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午8:57

_user = "smoke"
_passwd = "smoke520"

for i in range(3):
    username = input("Username:")
    password = input("Password:")

    if username == _user and password == _passwd:
        print("Welcome %s login..." % _user)
        break   #跳出，中断，break for过后，就不会执行最后的else语句
    else:
        print("Invalid username or password!")
else:    #只要上面的for循环正常执行完毕，中间没被打断，就会执行else语句
    print("要不要脸，愁流氓。")

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login.py
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
要不要脸，愁流氓。

Process finished with exit code 0

while

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午10:42

while True:
    print("当山峰没有棱角的时候")

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login_while.py
当山峰没有棱角的时候
当山峰没有棱角的时候
当山峰没有棱角的时候
当山峰没有棱角的时候
当山峰没有棱角的时候
当山峰没有棱角的时候

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午10:42

counter = 0
while True:
    if counter > 2**32:
        break
    counter += 1    #counter = counter + 1

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login_while.py

Process finished with exit code 0

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午10:42

counter = 0
while True:
    if counter > 2**16:
        break
    counter += 1    #counter = counter + 1

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login_while.py

Process finished with exit code 0

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午10:42

counter = 0
while True:
    if counter > 2**20:
        break
    counter += 1    #counter = counter + 1

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login_while.py

Process finished with exit code 0

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午10:42

counter = 0
while True:
    if counter > 2**25:
        break
    counter += 1    #counter = counter + 1

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login_while.py

Process finished with exit code 0

python2.x

[root@node1 ~]# python2
Python 2.7.5 (default, Apr 11 2018, 07:36:10) 
[GCC 4.8.5 20150623 (Red Hat 4.8.5-28)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> 2**25
33554432

编写登陆接口

输入用户名密码

认证成功后显示欢迎信息

错误三次后锁定

while

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午10:42

_user = "smoke"
_passwd = "smoke520"
while True:
    username = input("Username:")
    password = input("Password:")
    if username == _user and password == _passwd:
        print("Welcome %s login..." % _user)
        break   #跳出，中断
    else:
        print("Invalid username or password!")

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login_while.py
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
Username:    #无限循环

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午10:42

_user = "smoke"
_passwd = "smoke520"

counter = 0

while counter <3:
    username = input("Username:")
    password = input("Password:")
    if username == _user and password == _passwd:
        print("Welcome %s login..." % _user)
        break   #跳出，中断
    else:
        print("Invalid username or password!")

    counter += 1

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login_while.py
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!

Process finished with exit code 0

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午10:42

_user = "smoke"
_passwd = "smoke520"

counter = 0

while counter <3:
    username = input("Username:")
    password = input("Password:")
    if username == _user and password == _passwd:
        print("Welcome %s login..." % _user)
        break   #跳出，中断
    else:
        print("Invalid username or password!")

    counter += 1

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login_while.py
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke520
Welcome smoke login...

Process finished with exit code 0

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午10:42

_user = "smoke"
_passwd = "smoke520"

counter = 0

while counter <3:
    username = input("Username:")
    password = input("Password:")
    if username == _user and password == _passwd:
        print("Welcome %s login..." % _user)
        break   #跳出，中断
    else:
        print("Invalid username or password!")

    counter += 1
else:
    print("要不要脸，臭流氓。")

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login_while.py
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
要不要脸，臭流氓。

Process finished with exit code 0

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午10:42

_user = "smoke"
_passwd = "smoke520"

counter = 0

while counter <3:     #当while后面的条件成立(True),才会执行下面的代码
    username = input("Username:")
    password = input("Password:")
    if username == _user and password == _passwd:
        print("Welcome %s login..." % _user)
        break   #跳出，中断
    else:
        print("Invalid username or password!")

    counter += 1
else:
    print("要不要脸，臭流氓。")

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login_while.py
Username:smoke
Password:smoke520
Welcome smoke login...

Process finished with exit code 0

编写登陆接口

输入用户名密码

认证成功后显示欢迎信息

错误三次后询问是否继续，yes就继续，否则就退出

while

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午10:42

_user = "smoke"
_passwd = "smoke520"

counter = 0

while counter <3:
    username = input("Username:")
    password = input("Password:")
    if username == _user and password == _passwd:
        print("Welcome %s login..." % _user)
        break   #跳出，中断
    else:
        print("Invalid username or password!")
    counter += 1

    keep_going_choice = input("还想玩吗？[y/n]")
    if keep_going_choice == "y":
        counter = 0

else:
    print("要不要脸，臭流氓。")

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login_while.py
Username:smoke
Password:smoke
Invalid username or password!
还想玩吗？[y/n]    #不输入
Username:smoke
Password:smoke520
Welcome smoke login...

Process finished with exit code 0

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午10:42

_user = "smoke"
_passwd = "smoke520"

counter = 0

while counter <3:
    username = input("Username:")
    password = input("Password:")
    if username == _user and password == _passwd:
        print("Welcome %s login..." % _user)
        break   #跳出，中断
    else:
        print("Invalid username or password!")
    counter += 1

    keep_going_choice = input("还想玩吗？[y/n]")
    if keep_going_choice == "y":
        counter = 0

else:
    print("要不要脸，臭流氓。")

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login_while.py
Username:smoke
Password:smoke
Invalid username or password!
还想玩吗？[y/n]smoke
Username:smoke
Password:smoke
Invalid username or password!
还想玩吗？[y/n]smoke
Username:smoke
Password:smoke
Invalid username or password!
还想玩吗？[y/n]smoke    #一直询问还想玩吗？
要不要脸，臭流氓。

Process finished with exit code 0

#!/usr/bin/env python3.8
# __author: "smoke"
# date: 2020/11/23 下午10:42

_user = "smoke"
_passwd = "smoke520"

counter = 0

while counter <3:
    username = input("Username:")
    password = input("Password:")
    if username == _user and password == _passwd:
        print("Welcome %s login..." % _user)
        break   #跳出，中断
    else:
        print("Invalid username or password!")
    counter += 1
    if counter == 3:
        keep_going_choice = input("还想玩吗？[y/n]")
        if keep_going_choice == "y":
            counter = 0

else:
    print("要不要脸，臭流氓。")

/home/smoke/PycharmProjects/pythonProject/venv/bin/python /home/smoke/PycharmProjects/pythonProject/lean_python/login_while.py
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
还想玩吗？[y/n]y
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
Username:smoke
Password:smoke
Invalid username or password!
还想玩吗？[y/n]
要不要脸，臭流氓。

Process finished with exit code 0

pycharm给程序打断点

右键 --> Debug "login_while", Variables窗口程序里目前所有变量；

 

点击播放键，出现_user={str}'smoke'变量；

再点击播放键，出现_passwd={str}'smoke520'变量；

再点击播放键，出现counter={int}0

再点击播放键，点击Console输入用户名，密码，直到程序走完成；