Calling Python from Matlab / Can I use Python installed by Anaconda? / "NULL pointer returned from Python."

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Would love to use some Python code a colleague wrote. I already have Anaconda installed, so I really don't want to install another version of Python (and associated libraries).
Tried:
pe = ...
pyenv('Version',...
fullfile('e:\', 'anaconda3', 'python.exe'));
myPythonVersion = pe.Version
py.print("Hello, Python!")
Got:
>> pe = ...
pyenv('Version',...
fullfile('e:\', 'anaconda3', 'python.exe'));
myPythonVersion = pe.Version
py.print("Hello, Python!")
myPythonVersion =
"3.8"
NULL pointer returned from Python.
>> py
>> pe
pe =
PythonEnvironment with properties:
Version: "3.8"
Executable: "e:\anaconda3\python.exe"
Library: "e:\anaconda3\python38.dll"
Home: "e:\anaconda3"
Status: NotLoaded
ExecutionMode: OutOfProcess
>>
Matlab Version R2020a (happy to upgrade, just too lazy right now...)

Accepted Answer

Brian
Brian on 30 Sep 2022
Edited: Brian on 30 Sep 2022
Not sure what the best answer is for this issue.
Due to other circumstances, I needed to re-install Matlab and Anaconda. Now everything works:
>> pe = ...
pyenv('Version',...
fullfile('c:\', 'temp', 'anaconda3', 'python.exe'));
>> py.print("Hello, Python!")
Hello, Python!
Is this due to:
  • Re-installing Matlab?
  • Installing the latest version of Matlab (R2022b)?
  • Re-installing Anaconda?
  • Putting Anaconda on the C:\ ?
sorry, I don't know.
What I do know is that launching from the Anaconda prompt is not required.

More Answers (1)

Al Danial
Al Danial on 30 Sep 2022
Try this start-up sequence: first open an Anaconda Prompt or Anaconda PowerShell terminal. Then within that terminal window, type the path to the matlab executable (or is it a launch .bat file on Windows?). Or just type 'matlab' if it is in your system-wide search path.
Then within matlab just do
>> pyenv
with no arguments to see if matlab figured everything out on its own.

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