Question concerning array.array and C++

[Fabio]

Hi All,
I have a question concerning the use of array.array inside of C++ code I
wrote.

I am working with _big_ data files but some entries in these files are
usually bounded say between -5 to 40. Returning a Python list makes no
sense. In Python I always work with the array.array module which does
the trick. But now that I wrote my own C++ module for some preprocessing
I need the return array.array objects.

Consider the object

array.array('c',[40,40,40])

Can I create such an object from within the C++ layer and pass it to the
Python layer?

I already looked at arraymodule.c and tried to link the arraymodule.o
file to my code but then I have to mess around with extern "C" and the
like and it gets really messy.

Any help would be great!

Fabio

[Hrvoje Niksic]

[ Please consider posting to the capi-sig list, which is dedicated to
answering questions like yours.
http://mail.python.org/mailman/listinfo/capi-sig ]

Fabio <Au***********@gmx.netwrites:

Consider the object

array.array('c',[40,40,40])

Can I create such an object from within the C++ layer and pass it to
the Python layer?

Yes, simply access the array type object using getattr (the "."
operator), much like you would from Python, and instantiate the type
by calling it:

// import array
PyObject *array_module = PyImport_ImportModule("array");
if (!array_module)
goto error;

// array_type = array.array
PyObject *array_type = PyObject_GetAttrString(array_module, "array");
Py_DECREF(array_module);
if (!array_type)
goto error;

// array = array_type('c', [40, 40, 40])
PyObject *array = PyObject_CallFunction(array_type, "c[iii]", 'c', 40, 40, 40);
if (!array)
goto error;

// at this point you have (a new reference to) the array object