2021-09-12、while循环

1、无限循环形式：

APPLE = True
while APPLE:
    print('1')

2、设置限制循环的条件：

APPLE = 3
while APPLE <= 11:
    APPLE += 2
    print(APPLE)

3、while与else的结合使用：

APPLE = 3
while APPLE <= 11:
    APPLE += 2
    print(APPLE)
else:#当APPLE不满足APPLE <= 11时，会运行
    print('over')