mirror of https://github.com/python/cpython
48 lines
1.2 KiB
ReStructuredText
48 lines
1.2 KiB
ReStructuredText
.. highlightlang:: c
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.. _iterator:
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Iterator Protocol
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=================
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There are only a couple of functions specifically for working with iterators.
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.. c:function:: int PyIter_Check(PyObject *o)
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Return true if the object *o* supports the iterator protocol.
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.. c:function:: PyObject* PyIter_Next(PyObject *o)
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Return the next value from the iteration *o*. If the object is an iterator,
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this retrieves the next value from the iteration, and returns *NULL* with no
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exception set if there are no remaining items. If the object is not an
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iterator, :exc:`TypeError` is raised, or if there is an error in retrieving the
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item, returns *NULL* and passes along the exception.
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To write a loop which iterates over an iterator, the C code should look
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something like this::
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PyObject *iterator = PyObject_GetIter(obj);
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PyObject *item;
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if (iterator == NULL) {
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/* propagate error */
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}
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while (item = PyIter_Next(iterator)) {
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/* do something with item */
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...
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/* release reference when done */
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Py_DECREF(item);
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}
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Py_DECREF(iterator);
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if (PyErr_Occurred()) {
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/* propagate error */
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}
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else {
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/* continue doing useful work */
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}
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