Slice Objects — Python 3.13.7 documentation
Description: Ellipsis Object:

# Slice Objects

PyTypeObject PySlice_Type
  Part of the Stable ABI.

  The type object for slice objects. This is the same as `slice` in the Python layer.

int PySlice_Check(PyObject *ob)

  Return true if ob is a slice object; ob must not be `NULL`. This function always succeeds.

PyObject *PySlice_New(PyObject *start, PyObject *stop, PyObject *step)
  Return value: New reference. Part of the Stable ABI.

  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` with an exception set if the new object could not be allocated.

int PySlice_GetIndices(PyObject *slice, Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step)
  Part of the Stable ABI.

  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.

  Changed in version 3.2: The parameter type for the slice parameter was `PySliceObject*` before.

int PySlice_GetIndicesEx(PyObject *slice, Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step, Py_ssize_t *slicelength)
  Part of the Stable ABI.

  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.

  Return `0` on success and `-1` on error with an exception set.

  Note

  This function is considered not safe for resizable sequences. Its invocation should be replaced by a combination of `PySlice_Unpack()` and `PySlice_AdjustIndices()` where

      if (PySlice_GetIndicesEx(slice, length, &start, &stop, &step, &slicelength) < 0) {
          // return error
      }

  is replaced by

      if (PySlice_Unpack(slice, &start, &stop, &step) < 0) {
          // return error
      }
      slicelength = PySlice_AdjustIndices(length, &start, &stop, step);

  Changed in version 3.2: The parameter type for the slice parameter was `PySliceObject*` before.

  Changed in version 3.6.1: If `Py_LIMITED_API` is not set or set to the value between `0x03050400` and `0x03060000` (not including) or `0x03060100` or higher `PySlice_GetIndicesEx()` is implemented as a macro using `PySlice_Unpack()` and `PySlice_AdjustIndices()`. Arguments start, stop and step are evaluated more than once.

  Deprecated since version 3.6.1: If `Py_LIMITED_API` is set to the value less than `0x03050400` or between `0x03060000` and `0x03060100` (not including) `PySlice_GetIndicesEx()` is a deprecated function.

int PySlice_Unpack(PyObject *slice, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step)
  Part of the Stable ABI since version 3.7.

  Extract the start, stop and step data members from a slice object as C integers. Silently reduce values larger than `PY_SSIZE_T_MAX` to `PY_SSIZE_T_MAX`, silently boost the start and stop values less than `PY_SSIZE_T_MIN` to `PY_SSIZE_T_MIN`, and silently boost the step values less than `-PY_SSIZE_T_MAX` to `-PY_SSIZE_T_MAX`.

  Return `-1` with an exception set on error, `0` on success.

  Added in version 3.6.1.

Py_ssize_t PySlice_AdjustIndices(Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t step)
  Part of the Stable ABI since version 3.7.

  Adjust start/end slice indices assuming a sequence of the specified length. Out of bounds indices are clipped in a manner consistent with the handling of normal slices.

  Return the length of the slice. Always successful. Doesn’t call Python code.

  Added in version 3.6.1.

## Ellipsis Object

PyTypeObject PyEllipsis_Type
  Part of the Stable ABI.

  The type of Python `Ellipsis` object. Same as `types.EllipsisType` in the Python layer.

PyObject *Py_Ellipsis

  The Python `Ellipsis` object. This object has no methods. Like `Py_None`, it is an immortal singleton object.

  Changed in version 3.12: `Py_Ellipsis` is immortal.