On Tue, Mar 29, 2016 at 10:49 AM, Paul Moore <p.f.moore@gmail.com> wrote:

On 29 March 2016 at 08:22, Sven R. Kunze <srkunze@mail.de> wrote:
> Thinking more about it, that would even come in nicely with path separators:
>
> p'/{whereever}/{youwant}/{togo}'
>
> That'll finally an easy-to-write and readable path generation. Great idea,
> Stephen.

P(wherever)/youwant/togo

is as good, if not better - just "from pathlib import Path as P" (or
use Path(wherever) if you don't like unnecessary 1-letter aliases...)

Yes. I assume you meant P('/') /wherever/youwant/togo. Or with p-strings,

p'/' /wherever/youwant/togo

I'm not necessarily against Sven's version either, but my first thoughts about the power of combined pf strings would be something like this (assuming Sven's implicit f):

all_data = [p'data{i}.txt'.read_text() for i in range(1, 307)]

which would read the contents of data1.txt, data2.txt, ..., and data306.txt into a list.

And below, to the security issue raised by Sjoerd.

On Tue, Mar 29, 2016 at 10:46 AM, Sjoerd Job Postmus <sjoerdjob@sjec.nl> wrote:

On Tue, Mar 29, 2016 at 06:27:09PM +1100, Chris Angelico wrote:
> On Tue, Mar 29, 2016 at 6:22 PM, Sven R. Kunze <srkunze@mail.de> wrote:
> > Thinking more about it, that would even come in nicely with path separators:
> >
> > p'/{whereever}/{youwant}/{togo}'
> >
> > That'll finally an easy-to-write and readable path generation. Great idea,
> > Stephen.
>
> Agreed, although this introduces a new edge case: what if 'togo'
> contains a slash? Should this raise an exception, or should it be
> interpreted as a multi-part path component? Arguments can be put for
> both sides.

As we all know, togo is user input containing
../../../../../../../../../../../../../../../etc/passwd

How about

p'/' /wherever/youwant//togo

That is, the floordiv operator could be used to prevent 'togo' from going up the directory tree with "../../" or "/etc/passwd". The // would thus restrict the user (who provides `togo`) into /wherever/youwant/ and it its subdirectories.

-Koos