extending with C

[Pete Shinners]

Jesper Olsen wrote:

> I need to write a python extension in C, and the method interface should
> be able to handle "arrays of float".
> 
> In the python code, the array could be represented as a tupel, a list or 
> an array it is not really important.
> 
> The extension needs to be able to receive such arrays, and to return them
> to python.


here's a quick dirty sample, reading a set of floats from inside a tuple...


PyObject* do_floats(PyObject* self, PyObject* args)
{
	PyObject* tuple;
	float* floatlist;
	int size, loop;

	if(!PyArg_ParseTuple("O", &tuple))
		return NULL;
	if(!PyTuple_Check(tuple))
	{
		PyErr_SetString(PyExc_TypeError, "need tuple");
		return NULL;
	}

	size = PyTuple_Size(tuple);
	floatlist = PyMem_New(float, size);
	if(!floatlist)
		return NULL;
	for(loop = 0; loop<size; ++loop)
		floatlist[loop] = PyTuple_GET_ITEM(tuple, loop);

	/* DO SOMETHING WITH THE FLOATLIST HERE */

	PyMem_Del(floatlist);
	Py_INCREF(Py_None);
	return Py_None;
}


of course, my email composer probably parses this better than a real c 
compiler, so you might find some typos in there. :]