I used python c api and wish to get an array back from python. I returned a python array from the python side and want to transfer the PyObject* result into a c array so I can use it.
Is there anyway I can do that?
Side questions: In what circumstance trying to return an element in the array like
return arr[3]
will cause the PyObject_callobject return NULL?
return arr
does give me something
In Python an "array" is a list datatype. Look at the PyList_* functions in the C API. You can find this reference here for 2.7 and here for 3.5. The functions of interest are:
Py_ssize_t PyList_Size(PyObject *list) to get the number of list members
and
PyObject* PyList_GetItem(PyObject *list, Py_ssize_t index) to get a reference to the member at that index.
A simple use of malloc or similar allocator and a for loop should do the trick.
Also note that only borrowed references are involved, so no reference count maintenance of these objects via void Py_INCREF(PyObject *o) and void Py_DECREF(PyObject *o) is necessary.
PyObject *result into a C array, do you mean a C array ofPyObject *or do you want to translate those array member objects into a more native C representation as well?Pystring_fromstringbut it does matter what version of Python you are using (2.7 or 3.5). (Also, I should probably ask if you are using CPython or IronPython or PyPy - I'm guessing from your remarks that its CPython) The difference between 2.7 and 3.5 will determine whether or not unicode makes a difference withstr. In CPython 2.7strgenerally deals with narrow character data - not unicode. In 3.5 that distinction has been erased (all strings are unicode). The AP{I's are not compatible in this regard. Which version are you on?