Python上下文管理使用

import contextlib
from queue import Queue

@contextlib.contextmanager
def myOpen(file):
    f = open(file)
    try:
        yield f #返回f到with...as..语句中的f
    finally:
        f.close()
file = r"D:	ext.txt"
with myOpen(file) as f:
    #在执行这块代码时，会先执行worker_state中yield前面的代码
    #执行完这块代码后，会执行worker_state中finally的代码
    for line in f:
        print(line)