How to Find Out My Pythonpath Using Python

How do I find out my PYTHONPATH using Python?

sys.path might include items that aren't specifically in your PYTHONPATH environment variable. To query the variable directly, use:

import os
try:
    user_paths = os.environ['PYTHONPATH'].split(os.pathsep)
except KeyError:
    user_paths = []

How to get the PYTHONPATH in shell?

The environment variable PYTHONPATH is actually only added to the list of locations Python searches for modules. You can print out the full list in the terminal like this:

python -c "import sys; print(sys.path)"

Or if want the output in the UNIX directory list style (separated by :) you can do this:

python -c "import sys; print(':'.join(x for x in sys.path if x))"

Which will output something like this:

/usr/local/lib/python2.7/dist-packages/feedparser-5.1.3-py2.7.egg:/usr/local/lib/
python2.7/dist-packages/stripogram-1.5-py2.7.egg:/home/qiime/lib:/home/debian:/us
r/lib/python2.7:/usr/lib/python2.7/plat-linux2:/usr/lib/python2.7/lib-tk:/usr/lib
/python2.7/lib-old:/usr/lib/python2.7/lib- dynload:/usr/local/lib/python2.7/dist-
packages:/usr/lib/python2.7/dist-packages:/usr/lib/python2.7/dist-packages/PIL:/u
sr/lib/python2.7/dist-packages/gst-0.10:/usr/lib/python2.7/dist-packages/gtk-2.0:
/usr/lib/pymodules/python2.7

How can I find where Python is installed on Windows?

In your Python interpreter, type the following commands:

>>> import os
>>> import sys
>>> os.path.dirname(sys.executable)
'C:\\Python25'

Also, you can club all these and use a single line command. Open cmd and enter following command

python -c "import os, sys; print(os.path.dirname(sys.executable))"

how to print contents of PYTHONPATH

I suggest not to rely on the raw PYTHONPATH because it can vary depending on the OS.

Instead of the PYTHONPATH value in the os.environ dict, use sys.path from the sys module. This is preferrrable, because it is platform independent:

import sys
print(sys.path)

The value of sys.path is initialized from the environment variable PYTHONPATH, plus an installation-dependent default (depending on your OS). For more info see

https://docs.python.org/2/library/sys.html#sys.path

https://docs.python.org/3/library/sys.html#sys.path

Find full path of the Python interpreter?

sys.executable contains full path of the currently running Python interpreter.

import sys

print(sys.executable)

which is now documented here

How to retrieve a module's path?

import a_module
print(a_module.__file__)

Will actually give you the path to the .pyc file that was loaded, at least on Mac OS X. So I guess you can do:

import os
path = os.path.abspath(a_module.__file__)

You can also try:

path = os.path.dirname(a_module.__file__)

To get the module's directory.

How do I find the location of my Python site-packages directory?

There are two types of site-packages directories, global and per user.

Global site-packages ("dist-packages") directories are listed in sys.path when you run:
```
 python -m site
```
For a more concise list run getsitepackages from the site module in Python code:
```
 python -c 'import site; print(site.getsitepackages())'
```
Caution: In virtual environments getsitepackages is not available with older versions of virtualenv, sys.path from above will list the virtualenv's site-packages directory correctly, though. In Python 3, you may use the sysconfig module instead:
```
 python3 -c 'import sysconfig; print(sysconfig.get_paths()["purelib"])'
```
The per user site-packages directory (PEP 370) is where Python installs your local packages:
```
 python -m site --user-site
```
If this points to a non-existing directory check the exit status of Python and see python -m site --help for explanations.
Hint: Running pip list --user or pip freeze --user gives you a list of all installed per user site-packages.

Practical Tips

<package>.__path__ lets you identify the location(s) of a specific package: (details)

  $ python -c "import setuptools as _; print(_.__path__)"
  ['/usr/lib/python2.7/dist-packages/setuptools']

<module>.__file__ lets you identify the location of a specific module: (difference)
```
  $ python3 -c "import os as _; print(_.__file__)"
  /usr/lib/python3.6/os.py
```

Run pip show <package> to show Debian-style package information:

  $ pip show pytest
  Name: pytest
  Version: 3.8.2
  Summary: pytest: simple powerful testing with Python
  Home-page: https://docs.pytest.org/en/latest/
  Author: Holger Krekel, Bruno Oliveira, Ronny Pfannschmidt, Floris Bruynooghe, Brianna Laugher, Florian Bruhin and others
  Author-email: None
  License: MIT license
  Location: /home/peter/.local/lib/python3.4/site-packages
  Requires: more-itertools, atomicwrites, setuptools, attrs, pathlib2, six, py, pluggy

I can't locate my python path (but able to locate python3 path)

What version of MacOS are you running? Starting in 12.3, Python2 was removed from the system.

https://developer.apple.com/documentation/macos-release-notes/macos-12_3-release-notes

Python
Deprecations
Python 2.7 was removed from macOS in this update. Developers should use Python 3 or an alternative language instead. (39795874)

Can't find my PYTHONPATH

Python does some stuff up front when it is started, probably also setting that path in windows. Just set it and see, if it is changed in sys.path.

Setting environment variables in the Python docs say:

My Computer ‣ Properties ‣ Advanced ‣ Environment Variables