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✏️ Editing: list.rst.txt

.. highlightlang:: c

.. _listobjects:

List Objects
------------

.. index:: 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 ``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.

.. versionchanged:: 2.2
      Allowed subtypes to be accepted.

.. 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.

.. versionadded:: 2.2

.. 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`.

.. versionchanged:: 2.5
      This function used an :c:type:`int` for *size*. This might require
      changes in your code for properly supporting 64-bit systems.

.. c:function:: Py_ssize_t PyList_Size(PyObject *list)

.. index:: builtin: len

Return the length of the list object in *list*; this is equivalent to
   ``len(list)`` on a list object.

.. versionchanged:: 2.5
      This function returned an :c:type:`int`. This might require changes in
      your code for properly supporting 64-bit systems.

.. c:function:: Py_ssize_t PyList_GET_SIZE(PyObject *list)

Macro form of :c:func:`PyList_Size` without error checking.

.. versionchanged:: 2.5
      This macro returned an :c:type:`int`. This might require changes in your
      code for properly supporting 64-bit systems.

.. 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 positive, indexing from the end of the list is not
   supported.  If *index* is out of bounds, return *NULL* and set an
   :exc:`IndexError` exception.

.. versionchanged:: 2.5
      This function used an :c:type:`int` for *index*. This might require
      changes in your code for properly supporting 64-bit systems.

.. c:function:: PyObject* PyList_GET_ITEM(PyObject *list, Py_ssize_t i)

Macro form of :c:func:`PyList_GetItem` without error checking.

.. versionchanged:: 2.5
      This macro used an :c:type:`int` for *i*. This might require changes in
      your code for properly supporting 64-bit systems.

.. 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
   or ``-1`` on failure.

.. note::

This function "steals" a reference to *item* and discards a reference to
      an item already in the list at the affected position.

.. versionchanged:: 2.5
      This function used an :c:type:`int` for *index*. This might require
      changes in your code for properly supporting 64-bit systems.

.. 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.

.. note::

This macro "steals" a reference to *item*, and, unlike
      :c:func:`PyList_SetItem`, does *not* discard a reference to any item that
      it being replaced; any reference in *list* at position *i* will be
      leaked.

.. versionchanged:: 2.5
      This macro used an :c:type:`int` for *i*. This might require
      changes in your code for properly supporting 64-bit systems.

.. 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)``.

.. versionchanged:: 2.5
      This function used an :c:type:`int` for *index*. This might require
      changes in your code for properly supporting 64-bit systems.

.. 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]``.  Negative indices, as when slicing from Python, are not
   supported.

.. versionchanged:: 2.5
      This function used an :c:type:`int` for *low* and *high*. This might
      require changes in your code for properly supporting 64-bit systems.

.. 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.  Negative indices, as when
   slicing from Python, are not supported.

.. versionchanged:: 2.5
      This function used an :c:type:`int` for *low* and *high*. This might
      require changes in your code for properly supporting 64-bit systems.

.. 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:: builtin: tuple

Return a new tuple object containing the contents of *list*; equivalent to
   ``tuple(list)``.

MR SKB