Mailing List Archive

David Ascher wrote:
> Tip: To find out the directory of the currently executing program, use:
>
> import sys, os
> if __name__ == '__main__':
> _thisDir = ''
> else:
> _thisDir = os.path.split(sys.modules[__name__].__file__)[0]

David, what are the advantages over this?

_thisDir = os.path.split(sys.argv[0])[0]

Jeff Bauer
Rubicon, Inc.

Jeff Bauer <jbauer@rubic.com> wrote:
> David Ascher wrote:
> > Tip: To find out the directory of the currently executing program, use:
> >
> > import sys, os
> > if __name__ == '__main__':
> > _thisDir = ''
> > else:
> > _thisDir = os.path.split(sys.modules[__name__].__file__)[0]
>
> David, what are the advantages over this?
>
> _thisDir = os.path.split(sys.argv[0])[0]

as far as I can tell, David's method works for everything
*except* the main module, while your method works for
the main module, but not for anything else...

how about a combination?

import sys, os
if __name__ == '__main__':
_thisDir = sys.argv[0]
else:
_thisDir = sys.modules[__name__].__file__
_thisDir = os.path.split(_thisDir)[0]

</F>

"Fredrik Lundh" <fredrik@pythonware.com> writes:

> how about a combination?
>
> import sys, os
> if __name__ == '__main__':
> _thisDir = sys.argv[0]
> else:
> _thisDir = sys.modules[__name__].__file__

Eh, what's wrong with simply using __file__? It's a global in your
own module, remember!

> _thisDir = os.path.split(_thisDir)[0]

One more refinement: instead of os.path.split(x)[0], use
os.path.dirname(x).

The whole thing could become a one-liner:

_thisDir = os.path.dirname(__name__ == '__main__' and sys.argv[0] or __file__)

You could also use the little-known fact that sys.path[0] is the
script's directory; or the empty string if it's the current directory:

if __name__ == '__main__':
_thisDir = sys.path[0] or os.curdir
else:
_thisDir = os.path.dirname(__file__)

--Guido van Rossum (home page: http://www.python.org/~guido/)

Guido van Rossum wrote:
>
> "Fredrik Lundh" <fredrik@pythonware.com> writes:
>
> > how about a combination?
> >
> > import sys, os
> > if __name__ == '__main__':
> > _thisDir = sys.argv[0]
> > else:
> > _thisDir = sys.modules[__name__].__file__
>
> Eh, what's wrong with simply using __file__? It's a global in your
> own module, remember!

[I think we had that some months ago, already]

> if __name__ == '__main__':
> _thisDir = sys.path[0] or os.curdir
> else:
> _thisDir = os.path.dirname(__file__)

Since these come up again and again, I still see no reason why
we don't support __file__ for __main__?

Wouldn't it be much clearer to
1) provide an absolute path for __file__ always
2) provide __file__ for __main__ as
abs_path(sys.path[0] or os.curdir) + name_of_sciptfile?
If there is no scriptfile, well we'd take the empty string.

The other proposals are not as foolproof, since they depend
on weak stuff as os.curdir which has dynamic meaning, while
paths of files are a static thing, a "compile time" property
with early binding.

I'd like to be able to always use:

_thisDir = os.path.dirname(__file__)
_script = os.path.basename(__file__)

if _script:
# well, we have a script file

always? Even better

_thisdir, _script = os.path.split(__file__)

What is the background to keep this thing complicated for the user
(where complicated means to use more than one function call),
instead of the above?

ciao - chris

--
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