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Configure Your System to Use Python

Python Support

To call Python® modules in MATLAB®, you must have a supported version of the reference implementation (CPython) installed on your system. Install a distribution, such as those found at https://www.python.org/downloads/. MATLAB does not support CPython versions installed from the Microsoft® store. For supported version information, see Versions of Python Compatible with MATLAB Products by Release.

MATLAB selects and loads a Python interpreter when you type a Python expression from MATLAB using the py namespace, for example, py.list. To change the interpreter:

  • If Python is loaded in InProcess ExecutionMode, then restart MATLAB and run pyenv with the new version information.

  • If Python is loaded in OutOfProcess mode, restart MATLAB and run pyenv with the new version information.

MATLAB accesses these settings when loading the Python interpreter:

  • User settings for the Python environment, configured using the pyenv function. If the version you specify conflicts with the version specified by PYTHONHOME, then delete the environment variable before calling pyenv. The value set by pyenv is persistent across MATLAB sessions. For more information, see Set Python Version on Windows Platform or Set Python Version on Mac and Linux Platforms.

  • PYTHONHOME environment variable, specifies where to find the standard Python libraries if the value of pyenv.Status is NotLoaded. To view the value of the variable in MATLAB, type getenv("PYTHONHOME"). For more information, see Use PYTHONHOME Environment Variable.

  • System PATH environment variable. To view the system path in MATLAB, type getenv("PATH").

  • Windows registry.

To verify that Python is installed on your system, open the Python interpreter from your system prompt and call Python functions.

To determine which version MATLAB is using, call pyenv. For example, on Windows:

pe = pyenv

pe = 

  PythonEnvironment with properties:

          Version: "3.10"
       Executable: "C:\Users\username\AppData\Local\Programs\Python\Python310\pythonw.exe"
          Library: "C:\Users\username\AppData\Local\Programs\Python\Python310\python310.dll"
             Home: "C:\Users\username\AppData\Local\Programs\Python\Python310"
           Status: NotLoaded
    ExecutionMode: InProcess

On Linux:

pe = pyenv

pe = 

  PythonEnvironment with properties:

          Version: "3.9"
       Executable: "/usr/bin/python3"
          Library: "libpython3.9.so.1.0"
             Home: "/usr"
           Status: NotLoaded
    ExecutionMode: InProcess

Install Supported Python Implementation

If you get the error message Unable to resolve the name py.myfunc, you might have an installation problem.

Install Python in Virtual Environment

You can create a virtual environment for a specific version of Python using the Python venv module. You can also install the MATLAB Engine API for Python in a virtual environment. For venv instructions, see the MATLAB Answers™ article Python virtual environments with Python Interface. For information about virtual Python environments, see the Python tutorial Virtual Environments and Packages.

Set Python Version on Windows Platform

On Windows platforms, use either:

pyenv(Version="version")

or

pyenv(Version="executable")

where executable is the full path to the Python executable file. For more information, see the Version name-value argument for pyenv. For example, type:

pyenv(Version="3.11");

Note

If you downloaded a Python interpreter, but did not register it in the Windows registry, use:

pyenv(Version="executable")

For example, type:

pyenv(Version="C:\Users\username\AppData\Local\Programs\Python\Python311\python.exe");

Download 64-Bit Version of Python on Windows Platforms

The architecture of Python must match the architecture of MATLAB. For more information, see Install Supported Python Implementation.

Set Python Version on Mac and Linux Platforms

To set the version, type:

pyenv(Version="executable")

where executable is the full path to the Python executable file. For more information, see the Version name-value argument for pyenv. For example, type:

pyenv(Version="/usr/bin/python3.11")

Requirements for Building Python Executable

On Linux and Mac systems, if you build the Python executable, configure the build with the --enable-shared option.

Use PYTHONHOME Environment Variable

When possible, use pyenv to set the Python interpreter. In cases where pyenv is not usable, for example, when running MATLAB apps, an alternative way to set the interpreter is to use the PYTHONHOME environment variable. If you set the version with pyenv and PYTHONHOME, then the versions must be the same.

  • To view the variable in MATLAB, type getenv("PYTHONHOME"). To view the version set by pyenv, type e = pyenv; e.Version

  • To set PYTHONHOME, see https://docs.python.org/3/using/cmdline.html#envvar-PYTHONHOME. For information about setting environment variables, refer to your operating system documentation. You also can set the variable using setenv. However, this setting applies only to the current MATLAB session.

  • To delete PYTHONHOME for your current MATLAB session, type unsetenv("PYTHONHOME").

You cannot change the Python version if you have already loaded the interpreter. MATLAB loads a Python interpreter when you type a Python statement from MATLAB using the py namespace, for example, py.sys.path. To change the interpreter:

  • If Python is loaded in InProcess ExecutionMode in a single MATLAB session, then restart MATLAB and run pyenv with the new version information.

  • If Python is loaded in OutOfProcess mode, then call terminate and run pyenv with the new version information.

See Also

Related Topics

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