Use Python APIs in C#

Use Python APIs in C# with Python for .NET.

Requirements and syntax

Before writing your Python code, you have to:

  1. Ensure that Python is initialized with PythonRunner.EnsureInitialized().

  2. Grab the CPython Global Interpreter Lock (GIL).

Note

Using Py.GIL requires a reference to the Python.Runtime assembly: create a new assembly reference in Unity and set the Assembly Definition property to com.unity.scripting.python.editor.

In practice, the code structure in C# must look like this:

PythonRunner.EnsureInitialized();
using (Py.GIL())
{
    ...
    your code goes here
    ...
}

Example: log the current Python version in the Console

Code

The following C#/Python code creates a menu item that logs the current Python version in the Unity Console.

using Python.Runtime;
using UnityEditor;
using UnityEditor.Scripting.Python;

public class MyPythonScript
{
    [MenuItem("MyPythonScripts/Log Python Version")]
    public static void LogPythonVersion()
    {
        PythonRunner.EnsureInitialized();
        using (Py.GIL())
        {
            try
            {
                dynamic sys = Py.Import("sys");
                UnityEngine.Debug.Log($"python version: {sys.version}");
            }
            catch(PythonException e)
            {
                UnityEngine.Debug.LogException(e);
            }
        }
    }
}

Test

From the main menu of the Editor, select MyPythonScripts > Log Python Version.

The Python version currently used in your project should appear in the Unity Console.

Additional references