python_41_with语句

#为了避免打开文件后忘记关闭,可以通过管理上下文,即:with open('log','r') as f:
# 如此方式,当with代码块执行完毕时,内部会自动关闭并释放文件资源。
with open('yesterday','r',encoding='utf-8') as f:
    for line in f:#只是个例子
        print(line)
#注:python规范,一行代码不要超过80个字符。
#在Python 2.7 后,with又支持同时对多个文件的上下文进行管理,即:with open('log1') as obj1, open('log2') as obj2:
with open('yesterday','r',encoding='utf-8') as f,\
    open('yyy','r',encoding='utf-8') as f1:
    for line in f:#只是个例子
        print(line)
with open('mmm','w',encoding='utf-8') as f:
   f.write('aaaa')

  

posted @ 2018-01-20 20:57  耐烦不急  阅读(184)  评论(0编辑  收藏  举报