イテレータプロトコル (iterator protocol)

イテレータを扱うための固有の関数は二つあります。

int PyIter_Check(PyObject *o)

Part of the Stable ABI since version 3.8.

Return non-zero if the object o can be safely passed to PyIter_Next(), and 0 otherwise. This function always succeeds.

int PyAIter_Check(PyObject *o)

Part of the Stable ABI since version 3.10.

Return non-zero if the object o provides the AsyncIterator protocol, and 0 otherwise. This function always succeeds.

バージョン 3.10 で追加.

PyObject *PyIter_Next(PyObject *o)

Return value: New reference. Part of the Stable ABI.

Return the next value from the iterator o. The object must be an iterator according to PyIter_Check() (it is up to the caller to check this). If there are no remaining values, returns NULL with no exception set. If an error occurs while retrieving the item, returns NULL and passes along the exception.

イテレータの返す要素にわたって反復処理を行うループを書くと、C のコードは以下のようになるはずです:

PyObject *iterator = PyObject_GetIter(obj);
PyObject *item;

if (iterator == NULL) {
    /* propagate error */
}

while ((item = PyIter_Next(iterator))) {
    /* do something with item */
    ...
    /* release reference when done */
    Py_DECREF(item);
}

Py_DECREF(iterator);

if (PyErr_Occurred()) {
    /* propagate error */
}
else {
    /* continue doing useful work */
}

type PySendResult

The enum value used to represent different results of PyIter_Send().

バージョン 3.10 で追加.

PySendResult PyIter_Send(PyObject *iter, PyObject *arg, PyObject **presult)

Part of the Stable ABI since version 3.10.

Sends the arg value into the iterator iter. Returns:

• PYGEN_RETURN if iterator returns. Return value is returned via presult.

• PYGEN_NEXT if iterator yields. Yielded value is returned via presult.

• PYGEN_ERROR if iterator has raised and exception. presult is set to NULL.

バージョン 3.10 で追加.