How to add to the pythonpath in Windows?

Question

I have a directory which hosts all of my Django apps (C:\My_Projects). I want to add this directory to my pythonpath so I can call the apps directly.

I have tried adding C:\My_Projects\; to my Path variable from the Windows GUI (My Computer > Properties > Advanced System Settings > Environment Variables). But it still doesn't read the coltrane module and generates this error:

Error: No module named coltrane

Answer 1

Adding Python and PythonPath to the Windows environment:

1. Open Explorer.
2. Right-click 'Computer' in the Navigation Tree Panel on the left.
3. Select 'Properties' at the bottom of the Context Menu.
4. Select 'Advanced system settings'
5. Click 'Environment Variables...' in the Advanced Tab

6. Under 'System Variables':

   1. Add

      • PY_HOME

        C:\Python27
        

      • PYTHONPATH

        %PY_HOME%\Lib;%PY_HOME%\DLLs;%PY_HOME%\Lib\lib-tk;C:\another-library
        

   2. Append

      • path

        %PY_HOME%;%PY_HOME%\Scripts\
        

Answer 2

Windows 7 Professional I Modified @mongoose_za's answer to make it easier to change the python version:

1. [Right Click]Computer > Properties >Advanced System Settings > Environment Variables
2. Click [New] under "System Variable"
3. Variable Name: PY_HOME, Variable Value:C:\path\to\python\version
4. Click [OK]
5. Locate the "Path" System variable and click [Edit]

6. Add the following to the existing variable:

   %PY_HOME%;%PY_HOME%\Lib;%PY_HOME%\DLLs;%PY_HOME%\Lib\lib-tk;

7. Click [OK] to close all of the windows.

As a final sanity check open a command prompt and enter python. You should see

>python [whatever version you are using]

If you need to switch between versions, you only need to modify the PY_HOME variable to point to the proper directory. This is bit easier to manage if you need multiple python versions installed.

Answer 3

From Windows command line:

set PYTHONPATH=%PYTHONPATH%;C:\My_python_lib

To set the PYTHONPATH permanently, add the line to your autoexec.bat. Alternatively, if you edit the system variable through the System Properties, it will also be changed permanently.

Answer 4

This PYTHONPATH variable needs to be set for ArcPY when ArcGIS Desktop is installed.

PYTHONPATH=C:\arcgis\bin (your ArcGIS home bin)

For some reason it never was set when I used the installer on a Windows 7 32-bit system.

Answer 5

You know what has worked for me really well on windows.

My Computer > Properties > Advanced System Settings > Environment Variables >

Just add the path as C:\Python27 (or wherever you installed python)

OR

Then under system variables I create a new Variable called PythonPath. In this variable I have C:\Python27\Lib;C:\Python27\DLLs;C:\Python27\Lib\lib-tk;C:\other-folders-on-the-path

This is the best way that has worked for me which I hadn't found in any of the docs offered.

EDIT: For those who are not able to get it, Please add

C:\Python27;

along with it. Else it will never work.

Answer 6

In Python 3.4 on windows it worked when I added it to PATH enviroment variable instead of PYTHONPATH. Like if you have installed Python 3.4 in D:\Programming\Python34 then add this at the end of your PATH environment variable

;D:\Programming\Python34

Close and reopen command prompt and execute 'python'. It will open the python shell. This also fixed my Sublime 3 issue of 'python is not recognized as an internal or external command'.