PYTHON_VERSION get the Python version used by MATLAB

uses persistent variable to cache the Python version. If the environment changes, the cached version will be invalid. this persistent cache is cleared by "clear functions"

Contents

Inputs

Output

we need to do at least one Python function call to handle cases where the environment has changed since pyenv() was set. For example HPC with "module load python3..."

function [v, msg] = python_version(force_old)
if nargin < 1
  force_old = false;
end

persistent stdlib_py_version pyv_cached

msg = '';

if isempty(pyv_cached)
  pyv_cached = false;
elseif pyv_cached
  v = stdlib_py_version;
  return
end

% Matlab < R2022a has a bug in the JIT compiler that breaks try-catch
% for any py.* command.
% We use a separate private function to workaround that.

v = [];

if stdlib.matlabOlderThan('R2022a') && ~force_old
  return
end

% glitchy Python load can error on sys.version_info
try
  v = pvt_python_version();
catch e
  msg = e.message;
end

% cache the result - even if empty -- because the check takes up to 1000 ms say on HPC
stdlib_py_version = v;
pyv_cached = true;

end

Published with MATLAB® R2025a