PYTHONPATH?

[Dr. Pastor]

Several Documents about Python
refer to PYTHONPATH.
I could not find such variable.
(Python 2.4.2, IDLE 1.1.2, Windows XP)
How should/could I nominate a Directory to be
the local Directory?
Thanks for any guidance.

[Diez B. Roggisch]

Re: PYTHONPATH?

Dr. Pastor wrote:
[color=blue]
> Several Documents about Python
> refer to PYTHONPATH.
> I could not find such variable.
> (Python 2.4.2, IDLE 1.1.2, Windows XP)
> How should/could I nominate a Directory to be
> the local Directory?
> Thanks for any guidance.[/color]

It's a so called environment-variable. You can set these in some obscure
windows dialog in the system-preferences on a per-system or per-user base.
Or you start using cygwin (lots of good other reasons for that), and do

export PYTHONPATH=/whatever

Diez

[Magnus Lycka]

Re: PYTHONPATH?

Dr. Pastor wrote:[color=blue]
> Several Documents about Python refer to PYTHONPATH.[/color]

If you need to import libraries into Python, that don't reside in the
standard locations in your Python installation, you need to define
a PYTHONPATH environment variable in the operating system, which
points out this directory.

Defining this is done in the same way as defining PATH etc.
[color=blue]
> I could not find such variable.[/color]

Do you need it for anything?
[color=blue]
> (Python 2.4.2, IDLE 1.1.2, Windows XP)
> How should/could I nominate a Directory to be the local Directory?[/color]

import os
os.chdir('c:/somedir')

Another way is to start python from there, e.g. from the
command prompt (nothing beats a command prompt!) you would do:

cd some\local\dire ctory
python myscript.py (... or just python ...)

Note that backslash in a Python string literal denotes an escape
sequence. In Python 'c:\temp' means 'c' ':' tab 'e' 'm' 'p', since
'\t' is the escape sequence for a tab. You can use 'c:/temp' (ok
for Windows APIs) r'c:\temp' (r for raw string, i.e. don't use
escape sequences) or 'c:\\temp' (\\ is the escape sequence for
backslash).

Also note, that the way to use libraries from an arbitrary
directory without setting PYTHONPATH, is not with os.chdir,
but by doing this:

import sys
sys.path.append ('c:/somedir')

[Tombo]

Re: PYTHONPATH?

Said obscure dialog is here:
My Computer > Properties > Advanced (tab) > Environment Variables

You probably want a new system variable.

You can check the value by starting a new terminal window and typing:

echo %PYTHONPATH%

Cheers
Tombo

Diez B. Roggisch wrote:[color=blue]
> Dr. Pastor wrote:
>[color=green]
> > Several Documents about Python
> > refer to PYTHONPATH.
> > I could not find such variable.
> > (Python 2.4.2, IDLE 1.1.2, Windows XP)
> > How should/could I nominate a Directory to be
> > the local Directory?
> > Thanks for any guidance.[/color]
>
> It's a so called environment-variable. You can set these in some obscure
> windows dialog in the system-preferences on a per-system or per-user base.
> Or you start using cygwin (lots of good other reasons for that), and do
>
> export PYTHONPATH=/whatever
>
> Diez[/color]