.. 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)``.