I am trying to add a path to the PYTHONPATH environment variable, that would be only visible from a particular virtualenv environment.

I tried SET PYTHONPATH=... under a virtualenv command prompt, but that sets the variable for the whole environment.

How do I achieve that?

You can usually avoid having to do anything with PYTHONPATH by using .pth files. Just put a file with a .pth extension (any basename works) in your virtualenv’s site-packages folder, e.g. lib\python2.7\site-packages, with the absolute path to the directory containing your package as its only contents.

If you’re using virtualenv, you should probably also be using virtualenvwrapper, in which case you can use the add2virtualenv command to add paths to the Python path for the current virtualenv:

add2virtualenv directory1 directory2 …

You can also try to put symlink to one of your virtualenv.

eg. 1) activate your virtualenv 2) run python 3) import sys and check sys.path 4) you will find python search path there. Choose one of those (eg. site-packages) 5) go there and create symlink to your package like: ln -s path-to-your-package name-with-which-you’ll-be-importing

That way you should be able to import it even without activating your virtualenv. Simply try: path-to-your-virtualenv-folder/bin/python and import your package.

If you are using virtualenvwrapper,

$ cd to the parent folder
$ add2virtualenv  folder_to_add

console will display

Warning: Converting "folder_to_add" to "/absoutle/path/to/folder_to_add"

That’s it, and you should be good to go

import sys
import os

print(str(sys.path))

dir_path = os.path.dirname(os.path.realpath(__file__))
print("current working dir: %s" % dir_path)

sys.path.insert(0, dir_path)

I strongly suggest you use virtualenv and virtualenvwrapper to avoid cluttering the path.