Doc/c-api/slice.rst

.. highlightlang:: c

.. _slice-objects:

Slice Objects
-------------


.. cvar:: PyTypeObject PySlice_Type

   .. index:: single: SliceType (in module types)

   The type object for slice objects.  This is the same as ``slice`` and
   ``types.SliceType``.


.. cfunction:: int PySlice_Check(PyObject *ob)

   Return true if *ob* is a slice object; *ob* must not be *NULL*.


.. cfunction:: PyObject* PySlice_New(PyObject *start, PyObject *stop, PyObject *step)

   Return a new slice object with the given values.  The *start*, *stop*, and
   *step* parameters are used as the values of the slice object attributes of
   the same names.  Any of the values may be *NULL*, in which case the
   ``None`` will be used for the corresponding attribute.  Return *NULL* if
   the new object could not be allocated.


.. cfunction:: int PySlice_GetIndices(PySliceObject *slice, Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step)

   Retrieve the start, stop and step indices from the slice object *slice*,
   assuming a sequence of length *length*. Treats indices greater than
   *length* as errors.

   Returns 0 on success and -1 on error with no exception set (unless one of
   the indices was not :const:`None` and failed to be converted to an integer,
   in which case -1 is returned with an exception set).

   You probably do not want to use this function.

   .. versionchanged:: 2.5
      This function used an :ctype:`int` type for *length* and an
      :ctype:`int *` type for *start*, *stop*, and *step*. This might require
      changes in your code for properly supporting 64-bit systems.


.. cfunction:: 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)

   Usable replacement for :cfunc:`PySlice_GetIndices`.  Retrieve the start,
   stop, and step indices from the slice object *slice* assuming a sequence of
   length *length*, and store the length of the slice in *slicelength*.  Out
   of bounds indices are clipped in a manner consistent with the handling of
   normal slices.

   Returns 0 on success and -1 on error with exception set.

   .. versionchanged:: 2.5
      This function used an :ctype:`int` type for *length* and an
      :ctype:`int *` type for *start*, *stop*, *step*, and *slicelength*. This
      might require changes in your code for properly supporting 64-bit
      systems.