Python上下文管理使用

Posted 2020-09-23

 1 import contextlib
 2 from queue import Queue
 3 
 4 @contextlib.contextmanager
 5 def myOpen(file):
 6     f = open(file)
 7     try:
 8         yield f #返回f到with...as..语句中的f
 9     finally:
10         f.close()
11 file = r"D:\text.txt"
12 with myOpen(file) as f:
13     #在执行这块代码时，会先执行worker_state中yield前面的代码
14     #执行完这块代码后，会执行worker_state中finally的代码
15     for line in f:
16         print(line)