示例一：
AGE = 20

count = 0
while True:
    if count == 5:
        break
    GUESS = int(input("AGE:"))
    if GUESS == AGE :
        print("It is right!")
        break
    elif GUESS > AGE :
        print("It is bigger!")
    else:
        print("It is small!")
    count +=1

if count == 5:
    print("You hava tried too many times!")


示例二：
_user="root"
_passwd="okooo123"

count = 0
while count<3:
    username = input("user:")
    passwd = input("passwd:")

    if _user == username and _passwd == passwd:
        print("Welcome")
        break
    elif _user != username or _passwd !=passwd:
        print("username or password is wrong")
    count +=1
else:
    print("Too many times wrong !")
    
    
示例三：
user = "root"

count =0
while count <5:
    Guess = input("user:")
    if Guess == user:
        print("It is right!")
        break
    elif Guess != user:
        print("It is wrong!")
        count +=1
else:
    print("You input were wrong!")

上面的三個示例均可實現while循環的基本知識，建議使用示例二的寫法。

本文出自 “Dr小白” 博客，請務必保留此出處http://metis.blog.51cto.com/1203503/1954874

python 3 while 循環示例