python中的while循环

1、死循环学会用法

a = 1
while True:
    print(a)
    a +=1

2、无限次输入，直到输对，才退出

_age = 18

while True:
    guess_age = int(input("guess_age:"))
    if guess_age == _age:
        print("Good!!!!")
        break
    else:
        print("no,please input")

3、限制输入三次，超过三次，提示输入次数太多退出

_age = 18
count = 0
while count<3:
    guess_age = int(input("guess_age:"))
    if guess_age == _age:
        print("Good!!!!")
        break
    elif guess_age > _age:
        print("no,cai da le ...")
    else:
        print("no,cai xiao le ...")
    count +=1
else:
    print("you have tried too many times...quit")