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Python for .NET is a package that gives Python programmers nearly seamless integration with the .NET Common Language Runtime (CLR) and provides a powerful application scripting tool for .NET developer...

pythonnet - Python.NET

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Python.NET is a package that gives Python programmers nearly seamless integration with the .NET Common Language Runtime (CLR) and provides a powerful application scripting tool for .NET developers. It allows Python code to interact with the CLR, and may also be used to embed Python into a .NET application.

.. note:: The master branch of this repository tracks the ongoing development of version 3.0. Backports of patches to 2.5 are tracked in the backports-2.5 branch <https://github.com/pythonnet/pythonnet/tree/backports-2.5>_.

Calling .NET code from Python

Python.NET allows CLR namespaces to be treated essentially as Python packages.

.. code-block:: python

import clr from System import String from System.Collections import *

To load an assembly, use the AddReference function in the clr module:

.. code-block:: python

import clr clr.AddReference("System.Windows.Forms") from System.Windows.Forms import Form

Embedding Python in .NET

  • You must set Runtime.PythonDLL property or PYTHONNET_PYDLL environment variable starting with version 3.0, otherwise you will receive BadPythonDllException (internal, derived from MissingMethodException) upon calling Initialize. Typical values are python38.dll (Windows), libpython3.8.dylib (Mac), libpython3.8.so (most other Unix-like operating systems).
  • All calls to python should be inside a using (Py.GIL()) {/* Your code here */} block.
  • Import python modules using dynamic mod = Py.Import("mod"), then you can call functions as normal, eg mod.func(args).
  • Use mod.func(args, Py.kw("keywordargname", keywordargvalue)) or mod.func(args, keywordargname: keywordargvalue) to apply keyword arguments.
  • All python objects should be declared as dynamic type.
  • Mathematical operations involving python and literal/managed types must have the python object first, eg. np.pi * 2 works, 2 * np.pi doesn't.

Example


.. code-block:: csharp

   static void Main(string[] args)
   {
       using (Py.GIL())
       {
           dynamic np = Py.Import("numpy");
           Console.WriteLine(np.cos(np.pi * 2));

           dynamic sin = np.sin;
           Console.WriteLine(sin(5));

           double c = (double)(np.cos(5) + sin(5));
           Console.WriteLine(c);

           dynamic a = np.array(new List<float> { 1, 2, 3 });
           Console.WriteLine(a.dtype);

           dynamic b = np.array(new List<float> { 6, 5, 4 }, dtype: np.int32);
           Console.WriteLine(b.dtype);

           Console.WriteLine(a * b);
           Console.ReadKey();
       }
   }

Output:

.. code:: csharp

   1.0
   -0.958924274663
   -0.6752620892
   float64
   int32
   [  6.  10.  12.]



Resources
---------

Information on installation, FAQ, troubleshooting, debugging, and
projects using pythonnet can be found in the Wiki:

https://github.com/pythonnet/pythonnet/wiki

Mailing list
    https://mail.python.org/mailman/listinfo/pythondotnet
Chat
    https://gitter.im/pythonnet/pythonnet

.NET Foundation
---------------
This project is supported by the `.NET Foundation <https://dotnetfoundation.org>`_.

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