1.with语句的原理:
1.1with是对类进行操作,必须包括以下三个函数
1.1.1 def __enter__(self):return self 必须返回自己
1.1.2 def __exit__(self, exc_type, exc_val, exc_tb):关闭类之前做的操作
1.1.3 具体做事情的函数,名字随便起
2.直接见代码:
class OPEN():
def __enter__(self):
print("in")
return self
def __exit__(self, exc_type, exc_val, exc_tb):
print("out")
def do_something(self):
print("做一些事情")
with OPEN() as f:
f.do_something()
View Code
-----------------------------------------------------------------------------------------------------------------------------------------