切片物件
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PyTypeObject PySlice_Type

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

int PySlice_Check(PyObject *ob)

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

PyObject* PySlice_New(PyObject *start, PyObject *stop, PyObject *step)
    *Return value: New reference.*

   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.

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 "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.  If you want to use
   slice objects in versions of Python prior to 2.3, you would
   probably do well to incorporate the source of
   "PySlice_GetIndicesEx()", suitably renamed, in the source of your
   extension.

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

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 "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.

   2.3 版新加入.

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


Ellipsis Object
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PyObject *Py_Ellipsis

   The Python "Ellipsis" object.  This object has no methods.  It
   needs to be treated just like any other object with respect to
   reference counts.  Like "Py_None" it is a singleton object.
