The 'with' and 'as' Keywords

Programming is all about getting the computer to do the work. Is there a way to get Python to automatically close our files for us?

Of course there is. This is Python.

You may not know this, but file objects contain a special pair of built-in methods: __enter__() and __exit__(). The details aren't important, but what is important is that when a file object's __exit__() method is invoked, it automatically closes the file. How do we invoke this method? With with and as.

The syntax looks like this:

with open("file", "mode") as variable:
    # Read or write to the file
posted @ 2017-06-12 15:50  2021年的顺遂平安君  阅读(133)  评论(0编辑  收藏  举报