[Python-ideas] With expressions

[Andre Roberge]

On Thu, Aug 2, 2018 at 7:24 AM Thomas Nyberg via Python-ideas <
python-ideas at python.org> wrote:

> Is it true that Path('file').read_text() cl
> oses the file after the read?
> I think that is the sort of functionality that Ken is asking for.
> It's not clear to me by your linked documentation that it does. If it
> does, maybe that should be made more clear in that linked documentation?
>

Agreed. Then again, the documentation includes a link to the source at the
top and we find (
https://github.com/python/cpython/blob/3.7/Lib/pathlib.py#L1174)

docstring:  Open the file in text mode, read it, and close the file.

Or ...

>>> import pathlib >>> help(pathlib.Path.read_text) Help on function
read_text in module pathlib: read_text(self, encoding=None, errors=None)
Open the file in text mode, read it, and close the file.


The documentation would be improved if it used the text from the docstring
instead of its own one-line description.

André Roberge



> (Of course, maybe it's written there somewhere and I'm just blind...)
>
> Cheers,
> Thomas
>
> On 08/02/2018 11:53 AM, Paul Moore wrote:
> > On Thu, 2 Aug 2018 at 10:39, Ken Hilton <kenlhilton at gmail.com> wrote:
> >
> >> With expressions allow using the enter/exit semantics of the with
> statement inside an expression context. Examples:
> >>
> >>      contents = f.read() with open('file') as f #the most obvious one
> >>      multiplecontents = [f.read() with open(name) as f for name in
> names] #reading multiple files
> >>
> >> I don't know if it's worth making the "as NAME" part of the with
> mandatory in an expression - is this a valid use case?
> >>
> >>      data = database.selectrows() with threadlock
> >>
> >> Where this would benefit: I think the major use case is `f.read() with
> open('file') as f`. Previous documentation has suggested
> `open('file').read()` and rely on garbage collection; as the disadvantages
> of that became obvious, it transitioned to a method that couldn't be done
> in an expression:
> >
> > That use case is satisfied by pathlib:
> >
> > Path('file').read_text()
> >
> > see
> https://docs.python.org/3.7/library/pathlib.html#pathlib.Path.read_text
> >
> > Are there any other use cases? I don't see any real advantage here
> > other than the non-advantage of being able to write one-liners.
> > Paul
> > _______________________________________________
> > Python-ideas mailing list
> > Python-ideas at python.org
> > https://mail.python.org/mailman/listinfo/python-ideas
> > Code of Conduct: http://python.org/psf/codeofconduct/
> >
> _______________________________________________
> Python-ideas mailing list
> Python-ideas at python.org
> https://mail.python.org/mailman/listinfo/python-ideas
> Code of Conduct: http://python.org/psf/codeofconduct/
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-ideas/attachments/20180802/26253f3d/attachment-0001.html>