import threading,queue,time
import contextlib @contextlib.contextmanager
def fun(list_1,val):
list_1.append(val)
try:
yield
finally:
list_1.remove(val) q = queue.Queue() q.put('alxe')
li = [] with fun(li,1):
q.get()
class A:
def __enter__(self):
print ('__enter__() called') def __exit__(self, e_t, e_v, t_b):
print ('__exit__() called') with A() as a:
print('got instance')
from __future__ import with_statement
from contextlib import contextmanager @contextmanager
def context():
print ('entering the zone')
try:
yield
except Exception as e:
print ('with an error %s'%e)
raise e
else:
print ('with no error') with context():
print ('----in context call------')
文件打开关闭
import contextlib @contextlib.contextmanager
def myopen(file_path,mode):
f = open(file_path,mode,encoding='utf-8')
try:
yield f finally:
f.close() with myopen('D:\E\semantic/sd.txt','r') as file_obj:
print(file_obj.read())