cross platform accessing paths (windows, linux ...)

Mike Mazurek mike.mazurek at gmail.com
Thu Mar 12 13:36:27 CET 2009


You might want to look at the path module:

http://pypi.python.org/pypi/path.py/2.2

It will probably make your code more readable.

On Thu, Mar 12, 2009 at 8:10 AM, Vlastimil Brom <vlastimil.brom at gmail.com>wrote:

> Hi all,
> I'd like to ask for some advice on how to acomplish file access in a
> cross platform way.
> My application is a kind of viewer of text and corresponding image
> files (stored in separate subdirectories) and I'm going to deploy it
> as binaries for windows and source files (again in separate
> directories);
> Of course the text and image data should be shared for the source and
> executable version.
> The program should be runnable without instalation, e.g. directly from
> a CD-ROM, flashdisk etc. (supposing the working python ...
> installation while using the source version).
> the directory structure looks like:
> my_viewer
>  - src
>  - bin
>  - txt
>  - img
>
> While writing the source on windows, I didn't notice problems, as the
> simple path
> "../txt/text_1.txt"
> worked well with open(...). (script file executed with the associated
> python.exe)
> However on Linux (Kubuntu 8.0.4) the files in neighbour directories
> were not found most of the time (probably depending on how the script
> was run - console; file manager Krusader ...)
> After a lot of trials and gradually solving some corner issues, I
> ended up with:
>
> def path_from_pardir(path):
>    return
> os.path.realpath(os.path.normpath(os.path.join(os.path.dirname(__file__),
> os.pardir, path)))
> #  __file__ is substituted with sys.path[0] if not present
>
> real_path = path_from_pardir("txt/text_1.txt")
>
> The above seems to work both on windows and linux, but it very much
> looks like woodoo code for me;
> as I have rather limited experiences on Linux, I'd like to ask, how
> this would be best done in a cross platform way; or is the above realy
> the way to go?
> (I hope, using / as path separator should be fine, as it is also
> supported on windows and other OS would use the slash anyway; is it
> true, or do I have to use os.sep (which would complicate the code
> slightly more)?
> Are there any issues I'm likely to run into say on Mac with this approach?
>
> I'm using python 2.5.4 on windows XPp SP3, and the default python
> 2.5.2 on Kubuntu 8.0.4;
> (as I probably can't reasonably use 2.6 here for deployment with py2exe).
>
> Any hints or comments are much appreciated; thanks in advance!
>
> regards,
>   Vlasta
> --
> http://mail.python.org/mailman/listinfo/python-list
>
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