python-c-api

I wrote a Python/C extension function that was called by Python, How can return an 2d array int[][] to Python? static PyObject* inference_function(PyObject *self, PyObject *args) { PyObject* doc_lst; int K,V; double alpha,beta; int n_iter; if (!PyArg_ParseTuple(args, "Oiiddi", &doc_lst, &K,&V, &alpha,&beta,&n_iter)) { printf("传入参数错误！\n"); return NULL; } return Py_BuildValue("i", 1); } What kind of array are you using? One way, which I find convenient, is to use numpy arrays, and modify the data in place. Numpy already has a lot of great operations for manipulating integer arrays, so this is

I am developing a module for Python using a C API. How can I create a variable that is seen as global from Python? For example, if my module is module , I want to create a variable g that does this job: import module print module.g In particular, g is an integer. Solution from Alex Martelli PyObject *m = Py_InitModule("mymodule", mymoduleMethods); PyObject *v = PyLong_FromLong((long) 23); PyObject_SetAttrString(m, "g", v); Py_DECREF(v); You can use PyObject_SetAttrString in your module's initialization routine, with first argument o being (the cast to (PyObject*) of) your module, second

I have a C++ program that uses the C api to use a Python library of mine. Both the Python library AND the C++ code are multithreaded. In particular, one thread of the C++ program instantiates a Python object that inherits from threading.Thread . I need all my C++ threads to be able to call methods on that object. From my very first tries (I naively just instantiate the object from the main thread, then wait some time, then call the method) I noticed that the execution of the Python thread associated with the object just created stops as soon as the execution comes back to the C++ program. If

The Python C API function PyEval_EvalCode let's you execute compiled Python code. I want to execute a block of Python code as if it were executing within the scope of a function , so that it has its own dictionary of local variables which don't affect the global state. This seems easy enough to do, since PyEval_EvalCode lets you provide a Global and Local dictionary: PyObject* PyEval_EvalCode(PyCodeObject *co, PyObject *globals, PyObject *locals) The problem I run into has to do with how Python looks up variable names. Consider the following code, that I execute with PyEval_EvalCode : myvar =

Is one correct in stating the following: If a Python object is created in a C function, but the function doesn't return it, no INCREF is needed, but a DECREF is. [false]If the function does return it, you do need to INCREF , in the function that receives the return value.[/false] When assigning C typed variables as attributes, like double , int etc., to the Python object, no INCREF or DECREF is needed. Assigning Python objects as attributes to your other Python objects goes like this: PyObject *foo; foo = bar // A Python object tmp = self->foo; Py_INCREF(foo); self->foo = foo; Py_XDECREF(tmp);

How do I replicate the following Python code with the Python C API? class Sequence(): def __init__(self, max): self.max = max def data(self): i = 0 while i < self.max: yield i i += 1 So far, I have this: #include <Python/Python.h> #include <Python/structmember.h> /* Define a new object class, Sequence. */ typedef struct { PyObject_HEAD size_t max; } SequenceObject; /* Instance variables */ static PyMemberDef Sequence_members[] = { {"max", T_UINT, offsetof(SequenceObject, max), 0, NULL}, {NULL} /* Sentinel */ }; static int Sequence_Init(SequenceObject *self, PyObject *args, PyObject *kwds) { if