with应用

实例代码

# -*- coding: UTF-8
class demo(object):
    def __enter__(self):
        return self
    def __init__(self):
        print('init')
    def __exit__(self, exc_type, exc_val, exc_tb):
        print(exc_type)
        print(exc_val)
        print(exc_tb)
    def do_something(self):
        print('do')
        return 'do'


with demo() as d:
    d.do_something(1, 1)