`pythonnet` is a package that gives .NET programmers ability to

integrate Python engine and use Python libraries.

## Embedding Python in .NET

- You must set `Runtime.PythonDLL` property or `PYTHONNET_PYDLL` environment variable,

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 *nix). Full path may be required.

- 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)`.

You can also access Python objects via `PyObject` and dervied types

instead of using `dynamic`.

- Use `mod.func(args, Py.kw("keywordargname", keywordargvalue))` or

`mod.func(args, keywordargname: keywordargvalue)` to apply keyword

arguments.

- 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

```csharp

using var _ = 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:

```

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).