mirror of
https://github.com/python/cpython.git
synced 2024-11-27 23:47:29 +01:00
897bc6f928
* wording fixes in type.rst * grammar and punctuation in sys.rst * set: grammar fixes * structures: capitalization fix * grammar fixes for sequence * objects: point to Py_TYPE instead of direct object access * numbers: add more explicit Python equivalences * method: add missing period * memory: grammar fix * mapping: grammar fixes * long: grammar fix * iter: fix grammar for PyAIter_Check * init: grammar fix
73 lines
2.0 KiB
ReStructuredText
73 lines
2.0 KiB
ReStructuredText
.. highlight:: c
|
|
|
|
.. _iterator:
|
|
|
|
Iterator Protocol
|
|
=================
|
|
|
|
There are two functions specifically for working with iterators.
|
|
|
|
.. c:function:: int PyIter_Check(PyObject *o)
|
|
|
|
Return non-zero if the object *o* can be safely passed to
|
|
:c:func:`PyIter_Next`, and ``0`` otherwise. This function always succeeds.
|
|
|
|
.. c:function:: int PyAIter_Check(PyObject *o)
|
|
|
|
Return non-zero if the object *o* provides the :class:`AsyncIterator`
|
|
protocol, and ``0`` otherwise. This function always succeeds.
|
|
|
|
.. versionadded:: 3.10
|
|
|
|
.. c:function:: PyObject* PyIter_Next(PyObject *o)
|
|
|
|
Return the next value from the iterator *o*. The object must be an iterator
|
|
according to :c:func:`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.
|
|
|
|
To write a loop which iterates over an iterator, the C code should look
|
|
something like this::
|
|
|
|
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 */
|
|
}
|
|
|
|
|
|
.. c:type:: PySendResult
|
|
|
|
The enum value used to represent different results of :c:func:`PyIter_Send`.
|
|
|
|
.. versionadded:: 3.10
|
|
|
|
|
|
.. c:function:: PySendResult PyIter_Send(PyObject *iter, PyObject *arg, PyObject **presult)
|
|
|
|
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``.
|
|
|
|
.. versionadded:: 3.10
|