Function array_subscript

numpy/core/src/multiarray/mapping.c:1434–1712

* General function for indexing a NumPy array with a Python object. */

 * General function for indexing a NumPy array with a Python object.
 */
NPY_NO_EXPORT PyObject *
array_subscript(PyArrayObject *self, PyObject *op)
{
    int index_type;
    int index_num;
    int i, ndim, fancy_ndim;
    NPY_cast_info cast_info = {.func = NULL};

    /*
     * Index info array. We can have twice as many indices as dimensions
     * (because of None). The + 1 is to not need to check as much.
     */
    npy_index_info indices[NPY_MAXDIMS * 2 + 1];

    PyArrayObject *view = NULL;
    PyObject *result = NULL;

    PyArrayMapIterObject * mit = NULL;

    /* return fields if op is a string index */
    if (PyDataType_HASFIELDS(PyArray_DESCR(self))) {
        PyArrayObject *view;
        int ret = _get_field_view(self, op, &view);
        if (ret == 0){
            if (view == NULL) {
                return NULL;
            }
            return (PyObject*)view;
        }
    }

    /* Prepare the indices */
    index_type = prepare_index(self, op, indices, &index_num,
                               &ndim, &fancy_ndim, 1);

    if (index_type < 0) {
        return NULL;
    }

    /* Full integer index */
    else if (index_type == HAS_INTEGER) {
        char *item;
        if (get_item_pointer(self, &item, indices, index_num) < 0) {
            goto finish;
        }
        result = (PyObject *) PyArray_Scalar(item, PyArray_DESCR(self),
                                             (PyObject *)self);
        /* Because the index is full integer, we do not need to decref */
        return result;
    }

    /* Single boolean array */
    else if (index_type == HAS_BOOL) {
        result = (PyObject *)array_boolean_subscript(self,
                                    (PyArrayObject *)indices[0].object,
                                    NPY_CORDER);
        goto finish;
    }