How to configure the IDL python bridge when using WinPython distribution

When running the IDL to Python bridge on Windows, using a WinPython distribution, you may face the below error

IDL> >>>

>>> import numpy as np

% SPAWN: Error executing spawn command.
 

This error is usually due to missing environment variables which prevent the python command to be found when called from IDL

 

Another side effect is that python cannot be launched from cmd / DOS command

C:\Users\bcasson>python

'python' is not recognized as an internal or external command, operable program or batch file.

 

In order to fix this issue, the below environment variables should be defined as follow:

 

PATH=C:\Program Files\winpython\WPy64-3771\python-3.7.7.amd64\;C:\Program Files\Harris\IDLxx\bin\bin.x86_64;[+ your existing PATH]

Note: the paths to WinPython and to IDLxx should be set at the beginning of the PATH variable

 

PYTHONHOME= C:\Program Files\winpython\WPy64-3771\python-3.7.7.amd64\

 

PYTHONPATH=C:\Program Files\Harris\IDLxx\bin\bin.x86_64;C:\Program Files\Harris\IDLxx\lib\bridges

 

QT_PLUGIN_PATH=C:\Program Files\winpython\WPy64-3771\python-3.7.7.amd64\libs

 

Then restart IDL and try again to run python commands

IDL> >>>
>>>  import numpy as np
% Loaded DLM: PYTHON37.

 

 

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created by BC on 11/4/20 - reviewed by BC(US) on 11/4/2020