cpython/Doc/c-api/list.rst
Victor Stinner 3f8483cad2
gh-106168: PyTuple_SET_ITEM() now checks the index (#106164)
PyTuple_SET_ITEM() and PyList_SET_ITEM() now check the index argument
with an assertion if Python is built in debug mode or is built with
assertions.

* list_extend() and _PyList_AppendTakeRef() now set the list size
  before calling PyList_SET_ITEM().
* PyStructSequence_GetItem() and PyStructSequence_SetItem() now check
  the index argument: must be lesser than REAL_SIZE(op).
* PyStructSequence_GET_ITEM() and PyStructSequence_SET_ITEM() are now
  aliases to PyStructSequence_GetItem() and
  PyStructSequence_SetItem().
2023-06-28 03:45:57 +02:00

149 lines
4.8 KiB
ReStructuredText

.. highlight:: c
.. _listobjects:
List Objects
------------
.. index:: pair: object; list
.. c:type:: PyListObject
This subtype of :c:type:`PyObject` represents a Python list object.
.. c:var:: PyTypeObject PyList_Type
This instance of :c:type:`PyTypeObject` represents the Python list type.
This is the same object as :class:`list` in the Python layer.
.. c:function:: int PyList_Check(PyObject *p)
Return true if *p* is a list object or an instance of a subtype of the list
type. This function always succeeds.
.. c:function:: int PyList_CheckExact(PyObject *p)
Return true if *p* is a list object, but not an instance of a subtype of
the list type. This function always succeeds.
.. c:function:: PyObject* PyList_New(Py_ssize_t len)
Return a new list of length *len* on success, or ``NULL`` on failure.
.. note::
If *len* is greater than zero, the returned list object's items are
set to ``NULL``. Thus you cannot use abstract API functions such as
:c:func:`PySequence_SetItem` or expose the object to Python code before
setting all items to a real object with :c:func:`PyList_SetItem`.
.. c:function:: Py_ssize_t PyList_Size(PyObject *list)
.. index:: pair: built-in function; len
Return the length of the list object in *list*; this is equivalent to
``len(list)`` on a list object.
.. c:function:: Py_ssize_t PyList_GET_SIZE(PyObject *list)
Similar to :c:func:`PyList_Size`, but without error checking.
.. c:function:: PyObject* PyList_GetItem(PyObject *list, Py_ssize_t index)
Return the object at position *index* in the list pointed to by *list*. The
position must be non-negative; indexing from the end of the list is not
supported. If *index* is out of bounds (<0 or >=len(list)),
return ``NULL`` and set an :exc:`IndexError` exception.
.. c:function:: PyObject* PyList_GET_ITEM(PyObject *list, Py_ssize_t i)
Similar to :c:func:`PyList_GetItem`, but without error checking.
.. c:function:: int PyList_SetItem(PyObject *list, Py_ssize_t index, PyObject *item)
Set the item at index *index* in list to *item*. Return ``0`` on success.
If *index* is out of bounds, return ``-1`` and set an :exc:`IndexError`
exception.
.. note::
This function "steals" a reference to *item* and discards a reference to
an item already in the list at the affected position.
.. c:function:: void PyList_SET_ITEM(PyObject *list, Py_ssize_t i, PyObject *o)
Macro form of :c:func:`PyList_SetItem` without error checking. This is
normally only used to fill in new lists where there is no previous content.
Bounds checking is performed as an assertion if Python is built in
:ref:`debug mode <debug-build>` or :option:`with assertions
<--with-assertions>`.
.. note::
This macro "steals" a reference to *item*, and, unlike
:c:func:`PyList_SetItem`, does *not* discard a reference to any item that
is being replaced; any reference in *list* at position *i* will be
leaked.
.. c:function:: int PyList_Insert(PyObject *list, Py_ssize_t index, PyObject *item)
Insert the item *item* into list *list* in front of index *index*. Return
``0`` if successful; return ``-1`` and set an exception if unsuccessful.
Analogous to ``list.insert(index, item)``.
.. c:function:: int PyList_Append(PyObject *list, PyObject *item)
Append the object *item* at the end of list *list*. Return ``0`` if
successful; return ``-1`` and set an exception if unsuccessful. Analogous
to ``list.append(item)``.
.. c:function:: PyObject* PyList_GetSlice(PyObject *list, Py_ssize_t low, Py_ssize_t high)
Return a list of the objects in *list* containing the objects *between* *low*
and *high*. Return ``NULL`` and set an exception if unsuccessful. Analogous
to ``list[low:high]``. Indexing from the end of the list is not supported.
.. c:function:: int PyList_SetSlice(PyObject *list, Py_ssize_t low, Py_ssize_t high, PyObject *itemlist)
Set the slice of *list* between *low* and *high* to the contents of
*itemlist*. Analogous to ``list[low:high] = itemlist``. The *itemlist* may
be ``NULL``, indicating the assignment of an empty list (slice deletion).
Return ``0`` on success, ``-1`` on failure. Indexing from the end of the
list is not supported.
.. c:function:: int PyList_Sort(PyObject *list)
Sort the items of *list* in place. Return ``0`` on success, ``-1`` on
failure. This is equivalent to ``list.sort()``.
.. c:function:: int PyList_Reverse(PyObject *list)
Reverse the items of *list* in place. Return ``0`` on success, ``-1`` on
failure. This is the equivalent of ``list.reverse()``.
.. c:function:: PyObject* PyList_AsTuple(PyObject *list)
.. index:: pair: built-in function; tuple
Return a new tuple object containing the contents of *list*; equivalent to
``tuple(list)``.