test 1
上下文管理器,将生成器转化为上下文管理器
import contextlib @contextlib.contextmanager def a(): print(1) yield print(3) with a() as q: print(2)
test 2
使用上下文管理器,抽象出异常处理
import contextlib @contextlib.contextmanager def b(): try: yield except Exception as error: print('error:',error) with b(): 1/0
test 3
contextlib.closing 的使用时,要求方法中必须存在一个close的方法名称
import contextlib class c: def d(self): print('start') def close(self): print('game over!') with contextlib.closing(c()) as c_obj: print('contextlib.close()')
test 4
with 完成多个文件的读写操作
with open('a.jpg', 'rb') as from_file, open('b.jpg', 'wb') as to_file: to_file.write(from_file.read())