CODEWITHSUNDEEP
python
riwalk
riwalk

Reputation: 14233

Adding folder to Python's path permanently

I've written a library in python and I want it to reside in a common location on the file system.

From my script, I just want to do:

>>> import mylib

Now I understand that in order to do this, I can do this:

>>> import sys
>>> sys.path.append(r'C:\MyFolder\MySubFolder')
>>> import mylib

But I don't want to have to do that every time.

The question is: How do I add a folder to python's sys.path permanently? I would imagine that it would be an environment variable, but I can't find it.

It seems like it should be easy, but I can't find out how to do it.

Upvotes: 16

Views: 43000

Answers (4)

Julien Gorenflot
Julien Gorenflot

Reputation: 11

I don't know how general it is, but I have a "usercustomize" file lying around which is read when starting my shell. Maybe it's just because I am a newbie for who "environment variable" sounds scary... Anyway, that's how I permanently modify my sys.path

But as said, I don't know how general it is. I have python 2.7.3, installed with python(x,y) on windows 7. And this file is at

C:>Users>Me>Appdata>Roaming>Python>Python27>sitepackages> (Careful, Appdata is hidden folder)

and the file, as said, is "usercustomize.py" nothing special in that file. In my case, just my 3 imported paths:

import sys
sys.path.append('C:\\Users\\blablabla\\LPlot')
sys.path.append('C:\\Users\\bliblibli\\MTSim')
sys.path.append('C:\\Users\\blobloblo\\XP')

hope it helps too... And if not, don't hit me, I'm 100% newb. Or let's say 99.99%

Upvotes: 1

bobince
bobince

Reputation: 536339

Another possibility is to alter the sys.path in your sitecustomize.py, a script that is loaded as Python startup time. (It can be put anywhere on your existing path, and can do any setup tasks you like; I use it to set up tab completion with readline too.)

The site module offers a method that takes care of adding to sys.path without duplicates and with .pth files:

import site
site.addsitedir(r'C:\MyFolder\MySubFolder')

Upvotes: 5

Uku Loskit
Uku Loskit

Reputation: 42040

Deducing from the path you provided in your example here's a tutorial for setting the PYTHONPATH variable in Windows: http://docs.python.org/using/windows.html#excursus-setting-environment-variables

Upvotes: 6

nmichaels
nmichaels

Reputation: 50943

The PYTHONPATH environment variable will do it.

Upvotes: 17

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