Hi, I would like to convert a double array to an *existing* array of int32 using the C numpy API. I tried using PyArray_CastTo, but this gives me an array full of zeros instead of converting the items to int. I am doing something like the following to convert a PyArrayObject in_o of double: ndescr = PyArray_DescrNewFromType(NPY_INT32); /* should be equivalent to astype */ ar = (PyArrayObject*)PyArray_FromArray((PyArrayObject*)in_o, ndescr, NPY_FORCECAST); if (ar == NULL) { goto clean_ndescr; } /* Using C Api for casting */ dims = PyArray_DIMS(in_o); Py_INCREF(ndescr); casted = (PyArrayObject*)PyArray_Zeros(((PyArrayObject*)in_o)->nd, dims, ndescr, 0); if (casted == NULL) { goto clean_ar; } st = PyArray_CastTo((PyArrayObject*)in_o, casted); if (st) { goto clean_casted; } When using this code in python with a = numpy.linspace(0, 10, 101) as input, I got array([0, 0, 1, 1, 2, 2, 3, 3, 4, 5] for ar, and array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0]) for array casted. Can't PyArray_CastTo be used to 'unsafely' cast an array, or is there something I am missing ? cheers, David