如何从PyArrayObject获取值？

Question

I try to get values from list. It's defined in Python as:

Line1 = [[[146.0, 560.0], [337.0, 478.0]], 
         [[204.0, 612.0], [397.0, 536.0]],
         [[166.0, 437.0], [350.0, 434.0]], 
         [[166.0, 552.0], [350.0, 546.0]],
         [[146.0, 560.0], [337.0, 478.0]], 
         [[204.0, 612.0], [397.0, 536.0]],
         [[166.0, 437.0], [350.0, 434.0]], 
         [[166.0, 552.0], [350.0, 546.0]]] 

parsed into PyArrayObject by:

PyArrayObject *lineA = (PyArrayObject*) PyArray_FROMANY (objLineA, PyArray_DOUBLE, 3, 3, NPY_IN_ARRAY);
if (!lineA) {
    PyErr_SetString(PyExc_ValueError, "expected [Layer][point][x] ");
       return NULL;
}

Till now everything seems to be OK, dimensions are OK. But when im trying:

struct pPoint {
    float x;
    float y;
};
...

struct pPoint p1a, p1b;

...
    p1a.x = *((float * )PyArray_GETPTR3(lineA, 0, 0, 0));
    p1a.y = *((float * )PyArray_GETPTR3(lineA, 0, 0, 1));
    p1b.x = *((float * )PyArray_GETPTR3(lineA, 0, 1, 0));
    p1b.y = *((float * )PyArray_GETPTR3(lineA, 0, 1, 1));
...

all values are ZERO.

What is a best and easiest way to get values from PyObjArray? Why 0.0?

Answer 1

I met the same problem. When I print out the value, it is always 0.0. Try to change all 'float' to 'double' in C. The float type in Python is the double type in C. You also claimed its type as PyArray_DOUBLE.