Opening files without closing them
Steven Bethard
steven.bethard at gmail.com
Sun Mar 5 19:36:47 EST 2006
Sandra-24 wrote:
> I was reading over some python code recently, and I saw something like
> this:
>
> contents = open(file).read()
>
> And of course you can also do:
>
> open(file, "w").write(obj)
>
> Why do they no close the files? Is this sloppy programming or is the
> file automatically closed when the reference is destroyed (after this
> line)? I usually use:
>
> try:
> f = open(file)
> contents = f.read()
> finally:
> f.close()
>
> But now I am wondering if that is the same thing. Which method would
> you rather use? Why?
In Python 2.5, you'll write::
with open(file) as f:
contents = f.read()
and Python will automatically close the file at the end of the
with-statement. Observe:
Python 2.5a0 (trunk:42857M, Mar 5 2006, 14:50:28) [MSC v.1310 32 bit
(Intel)] on win32
>>> from __future__ import with_statement
>>> with open('readme.txt') as f:
... contents = f.read()
...
>>> f
<closed file 'readme.txt', mode 'r' at 0x00B8BAA8>
Of course, you have to wait until August or so for Python 2.5:
http://www.python.org/peps/pep-0356.html
STeVe
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