ImportError : No module named '_ctypes'

[MaximG1234]

Environment

• Pythonnet version: 2.3.0.0
• Python version: 3.5.4
• Operating System: Windows 10 Pro Version 1803

I am trying to use Python.NET to perform interop between C# and Python on a Windows machine.

Specifically I have the following code.

PythonEngine.PythonHome = @"C:\Python\3_5_4";
PythonEngine.PythonPath = @"C:\Python\3_5_4\Lib;C:\Python\3_5_4\Lib\site-packages";

using (Python.Runtime.Py.GIL())
{
    dynamic np = Py.Import("numpy");
    dynamic sin = np.sin;
    Console.WriteLine(sin);
}

While I can successfully execute a general python statement as such:

var res = PythonEngine.Eval("1 + 1");
Console.WriteLine(res);
//res = 2

Which indicates that the python engine itself is working successfully, I can also invoke something like this:

var html = Py.Import("html");
Console.WriteLine(html);
//html = <module 'html' from 'C:\\Python\\3_5_4\\Lib\\html\\__init__.py'>

Which further indicates that the module loading functionality is also working correctly.

However whenever I attempt to invoke the line:

dynamic np = Py.Import("numpy"); 

I receive the following error:

{"ImportError : No module named '_ctypes'"}.

['  File "C:\\Python\\3_5_4\\Lib\\site-packages\\numpy\\__init__.py", line 140, in <module>\n    from . import _distributor_init\n', '  File "C:\\Python\\3_5_4\\Lib\\site-packages\\numpy\\_distributor_init.py", line 9, in <module>\n    from ctypes import WinDLL\n', '  File "C:\\Python\\3_5_4\\Lib\\ctypes\\__init__.py", line 8, in <module>\n    from _ctypes import Union, Structure, Array\n']

The file referenced is located @ C:\Python\3_5_4\Lib\ctypes\__init__.py.

I have verified that all the expected paths are set correctly and that the Ctypes folder exists in my python path.

I have tried everything from uninstalling and reinstalling Python to modifying the ctypes/__init__.py file to try and import Ctypes directly to no effect.

Having researched this topic online throughly I have found a number of suggestions which point to running yum install libffi-devel as detailed here. However this does not appear to be something that I can perform on windows given that yum appears to be a Linux only application.

Can anyone provide any guidance?

[filmor]

Ctypes is included in the standard library, the referenced module are the compiled parts of it, try to reinstall Python itself.

[nguyenvuduc]

@MaximG1234 : _ctypes.pyd is in PYTHONHOME/DLLs. You should include the directory in your PYTHONPATH environment variable. I can confirm that it will work as I already tried it by myself.

[StackChan]

@nguyenvuduc You save my day.Sincere thanks for u.