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

2、無限次輸入，直到輸對，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、限制輸入三次，超過三次，提示輸入次數太多退出

_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")
 

python中的while循環