contextlib- with语句节省代码量

from contextlib import contextmanager
@contextmanager
def make_open_context(filename, mode):
    fp = open(filename, mode)
    try:
        yield fp
    finally:
        fp.close()
with make_open_context('/tmp/a.txt', 'a') as file_obj:
    file_obj.write("hello carson666")

# _*_ coding:utf-8 _*_
from contextlib import contextmanager
"""
contextmanager给了我们一个机会，即将原来不是上下文管理器的类变成了一个
上下文管理器，例如这里的MyResource类
"""
class MyResource:
    def query(self):
        print("query data")
@contextmanager
def make_myresource():
    print("connect to resource")
    yield MyResource()
    print("connect to resource")
with make_myresource() as r:
    r.query()

案例3

模块functools

(36条消息) python functools 使用详解_寻寻觅觅oO的博客-CSDN博客_functools