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Re: context managers inline?

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On Fri, Mar 11, 2016 at 5:33 AM, Neal Becker <ndbecker2@gmail.com> wrote:
> Is there a way to ensure resource cleanup with a construct such as:
>
> x = load (open ('my file', 'rb))
>
> Is there a way to ensure this file gets closed?

Yep!

def read_file(fn, *a, **kw):
    with open(fn, *a, **kw) as f:
        return f.read()

Now you can ensure resource cleanup, because the entire file has been
read in before the function returns. As long as your load() function
is okay with reading from a string, this is effective.

Alternatively, push the closing the other way: pass a file name to
your load() function, and have the context manager in there.

If you don't do it one of those ways, the question is: WHEN should the
file be closed? How does Python know when it should go and clean that
up? There's no "end of current expression" rule as there is in C++, so
it's safer to use the statement form, which has a definite end (at the
unindent).

ChrisA

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Re: context managers inline? Chris Angelico <rosuav@gmail.com> - 2016-03-11 07:17 +1100
  Re: context managers inline? Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-03-11 08:09 +0200
    Re: context managers inline? Paul Rubin <no.email@nospam.invalid> - 2016-03-10 23:30 -0800
      Re: context managers inline? Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-03-11 11:16 +0200

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