1.. highlightlang:: c
2
3.. _slice-objects:
4
5Slice Objects
6-------------
7
8
9.. c:var:: PyTypeObject PySlice_Type
10
11   .. index:: single: SliceType (in module types)
12
13   The type object for slice objects.  This is the same as ``slice`` and
14   ``types.SliceType``.
15
16
17.. c:function:: int PySlice_Check(PyObject *ob)
18
19   Return true if *ob* is a slice object; *ob* must not be *NULL*.
20
21
22.. c:function:: PyObject* PySlice_New(PyObject *start, PyObject *stop, PyObject *step)
23
24   Return a new slice object with the given values.  The *start*, *stop*, and
25   *step* parameters are used as the values of the slice object attributes of
26   the same names.  Any of the values may be *NULL*, in which case the
27   ``None`` will be used for the corresponding attribute.  Return *NULL* if
28   the new object could not be allocated.
29
30
31.. c:function:: int PySlice_GetIndices(PySliceObject *slice, Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step)
32
33   Retrieve the start, stop and step indices from the slice object *slice*,
34   assuming a sequence of length *length*. Treats indices greater than
35   *length* as errors.
36
37   Returns ``0`` on success and ``-1`` on error with no exception set (unless one of
38   the indices was not :const:`None` and failed to be converted to an integer,
39   in which case ``-1`` is returned with an exception set).
40
41   You probably do not want to use this function.  If you want to use slice
42   objects in versions of Python prior to 2.3, you would probably do well to
43   incorporate the source of :c:func:`PySlice_GetIndicesEx`, suitably renamed,
44   in the source of your extension.
45
46   .. versionchanged:: 2.5
47      This function used an :c:type:`int` type for *length* and an
48      :c:type:`int *` type for *start*, *stop*, and *step*. This might require
49      changes in your code for properly supporting 64-bit systems.
50
51
52.. c:function:: int PySlice_GetIndicesEx(PySliceObject *slice, Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step, Py_ssize_t *slicelength)
53
54   Usable replacement for :c:func:`PySlice_GetIndices`.  Retrieve the start,
55   stop, and step indices from the slice object *slice* assuming a sequence of
56   length *length*, and store the length of the slice in *slicelength*.  Out
57   of bounds indices are clipped in a manner consistent with the handling of
58   normal slices.
59
60   Returns ``0`` on success and ``-1`` on error with exception set.
61
62   .. versionadded:: 2.3
63
64   .. versionchanged:: 2.5
65      This function used an :c:type:`int` type for *length* and an
66      :c:type:`int *` type for *start*, *stop*, *step*, and *slicelength*. This
67      might require changes in your code for properly supporting 64-bit
68      systems.
69
70
71Ellipsis Object
72---------------
73
74
75.. c:var:: PyObject *Py_Ellipsis
76
77   The Python ``Ellipsis`` object.  This object has no methods.  It needs to be
78   treated just like any other object with respect to reference counts.  Like
79   :c:data:`Py_None` it is a singleton object.
80