1 .. highlightlang:: c

     2 

     3 .. _listobjects:

     4 

     5 List Objects

     6 ------------

     7 

     8 .. index:: object: list

     9 

    10 

    11 .. ctype:: PyListObject

    12 

    13    This subtype of :ctype:`PyObject` represents a Python list object.

    14 

    15 

    16 .. cvar:: PyTypeObject PyList_Type

    17 

    18    .. index:: single: ListType (in module types)

    19 

    20    This instance of :ctype:`PyTypeObject` represents the Python list type.  This is

    21    the same object as ``list`` and ``types.ListType`` in the Python layer.

    22 

    23 

    24 .. cfunction:: int PyList_Check(PyObject *p)

    25 

    26    Return true if *p* is a list object or an instance of a subtype of the list

    27    type.

    28 

    29    .. versionchanged:: 2.2

    30       Allowed subtypes to be accepted.

    31 

    32 

    33 .. cfunction:: int PyList_CheckExact(PyObject *p)

    34 

    35    Return true if *p* is a list object, but not an instance of a subtype of the

    36    list type.

    37 

    38    .. versionadded:: 2.2

    39 

    40 

    41 .. cfunction:: PyObject* PyList_New(Py_ssize_t len)

    42 

    43    Return a new list of length *len* on success, or *NULL* on failure.

    44 

    45    .. note::

    46 

    47       If *length* is greater than zero, the returned list object's items are set to

    48       ``NULL``.  Thus you cannot use abstract API functions such as

    49       :cfunc:`PySequence_SetItem`  or expose the object to Python code before setting

    50       all items to a real object with :cfunc:`PyList_SetItem`.

    51 

    52 

    53 .. cfunction:: Py_ssize_t PyList_Size(PyObject *list)

    54 

    55    .. index:: builtin: len

    56 

    57    Return the length of the list object in *list*; this is equivalent to

    58    ``len(list)`` on a list object.

    59 

    60 

    61 .. cfunction:: Py_ssize_t PyList_GET_SIZE(PyObject *list)

    62 

    63    Macro form of :cfunc:`PyList_Size` without error checking.

    64 

    65 

    66 .. cfunction:: PyObject* PyList_GetItem(PyObject *list, Py_ssize_t index)

    67 

    68    Return the object at position *pos* in the list pointed to by *p*.  The position

    69    must be positive, indexing from the end of the list is not supported.  If *pos*

    70    is out of bounds, return *NULL* and set an :exc:`IndexError` exception.

    71 

    72 

    73 .. cfunction:: PyObject* PyList_GET_ITEM(PyObject *list, Py_ssize_t i)

    74 

    75    Macro form of :cfunc:`PyList_GetItem` without error checking.

    76 

    77 

    78 .. cfunction:: int PyList_SetItem(PyObject *list, Py_ssize_t index, PyObject *item)

    79 

    80    Set the item at index *index* in list to *item*.  Return ``0`` on success or

    81    ``-1`` on failure.

    82 

    83    .. note::

    84 

    85       This function "steals" a reference to *item* and discards a reference to an item

    86       already in the list at the affected position.

    87 

    88 

    89 .. cfunction:: void PyList_SET_ITEM(PyObject *list, Py_ssize_t i, PyObject *o)

    90 

    91    Macro form of :cfunc:`PyList_SetItem` without error checking. This is normally

    92    only used to fill in new lists where there is no previous content.

    93 

    94    .. note::

    95 

    96       This function "steals" a reference to *item*, and, unlike

    97       :cfunc:`PyList_SetItem`, does *not* discard a reference to any item that it

    98       being replaced; any reference in *list* at position *i* will be leaked.

    99 

   100 

   101 .. cfunction:: int PyList_Insert(PyObject *list, Py_ssize_t index, PyObject *item)

   102 

   103    Insert the item *item* into list *list* in front of index *index*.  Return ``0``

   104    if successful; return ``-1`` and set an exception if unsuccessful.  Analogous to

   105    ``list.insert(index, item)``.

   106 

   107 

   108 .. cfunction:: int PyList_Append(PyObject *list, PyObject *item)

   109 

   110    Append the object *item* at the end of list *list*. Return ``0`` if successful;

   111    return ``-1`` and set an exception if unsuccessful.  Analogous to

   112    ``list.append(item)``.

   113 

   114 

   115 .. cfunction:: PyObject* PyList_GetSlice(PyObject *list, Py_ssize_t low, Py_ssize_t high)

   116 

   117    Return a list of the objects in *list* containing the objects *between* *low*

   118    and *high*.  Return *NULL* and set an exception if unsuccessful. Analogous to

   119    ``list[low:high]``.

   120 

   121 

   122 .. cfunction:: int PyList_SetSlice(PyObject *list, Py_ssize_t low, Py_ssize_t high, PyObject *itemlist)

   123 

   124    Set the slice of *list* between *low* and *high* to the contents of *itemlist*.

   125    Analogous to ``list[low:high] = itemlist``. The *itemlist* may be *NULL*,

   126    indicating the assignment of an empty list (slice deletion). Return ``0`` on

   127    success, ``-1`` on failure.

   128 

   129 

   130 .. cfunction:: int PyList_Sort(PyObject *list)

   131 

   132    Sort the items of *list* in place.  Return ``0`` on success, ``-1`` on failure.

   133    This is equivalent to ``list.sort()``.

   134 

   135 

   136 .. cfunction:: int PyList_Reverse(PyObject *list)

   137 

   138    Reverse the items of *list* in place.  Return ``0`` on success, ``-1`` on

   139    failure.  This is the equivalent of ``list.reverse()``.

   140 

   141 

   142 .. cfunction:: PyObject* PyList_AsTuple(PyObject *list)

   143 

   144    .. index:: builtin: tuple

   145 

   146    Return a new tuple object containing the contents of *list*; equivalent to

   147    ``tuple(list)``.