1.. highlightlang:: c 2 3.. _slice-objects: 4 5Slice Objects 6------------- 7 8 9.. c:var:: PyTypeObject PySlice_Type 10 11 The type object for slice objects. This is the same as :class:`slice` in the 12 Python layer. 13 14 15.. c:function:: int PySlice_Check(PyObject *ob) 16 17 Return true if *ob* is a slice object; *ob* must not be *NULL*. 18 19 20.. c:function:: PyObject* PySlice_New(PyObject *start, PyObject *stop, PyObject *step) 21 22 Return a new slice object with the given values. The *start*, *stop*, and 23 *step* parameters are used as the values of the slice object attributes of 24 the same names. Any of the values may be *NULL*, in which case the 25 ``None`` will be used for the corresponding attribute. Return *NULL* if 26 the new object could not be allocated. 27 28 29.. c:function:: int PySlice_GetIndices(PyObject *slice, Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step) 30 31 Retrieve the start, stop and step indices from the slice object *slice*, 32 assuming a sequence of length *length*. Treats indices greater than 33 *length* as errors. 34 35 Returns ``0`` on success and ``-1`` on error with no exception set (unless one of 36 the indices was not :const:`None` and failed to be converted to an integer, 37 in which case ``-1`` is returned with an exception set). 38 39 You probably do not want to use this function. 40 41 .. versionchanged:: 3.2 42 The parameter type for the *slice* parameter was ``PySliceObject*`` 43 before. 44 45 46.. c:function:: 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) 47 48 Usable replacement for :c:func:`PySlice_GetIndices`. Retrieve the start, 49 stop, and step indices from the slice object *slice* assuming a sequence of 50 length *length*, and store the length of the slice in *slicelength*. Out 51 of bounds indices are clipped in a manner consistent with the handling of 52 normal slices. 53 54 Returns ``0`` on success and ``-1`` on error with exception set. 55 56 .. note:: 57 This function is considered not safe for resizable sequences. 58 Its invocation should be replaced by a combination of 59 :c:func:`PySlice_Unpack` and :c:func:`PySlice_AdjustIndices` where :: 60 61 if (PySlice_GetIndicesEx(slice, length, &start, &stop, &step, &slicelength) < 0) { 62 // return error 63 } 64 65 is replaced by :: 66 67 if (PySlice_Unpack(slice, &start, &stop, &step) < 0) { 68 // return error 69 } 70 slicelength = PySlice_AdjustIndices(length, &start, &stop, step); 71 72 .. versionchanged:: 3.2 73 The parameter type for the *slice* parameter was ``PySliceObject*`` 74 before. 75 76 .. versionchanged:: 3.6.1 77 If ``Py_LIMITED_API`` is not set or set to the value between ``0x03050400`` 78 and ``0x03060000`` (not including) or ``0x03060100`` or higher 79 :c:func:`!PySlice_GetIndicesEx` is implemented as a macro using 80 :c:func:`!PySlice_Unpack` and :c:func:`!PySlice_AdjustIndices`. 81 Arguments *start*, *stop* and *step* are evaluated more than once. 82 83 .. deprecated:: 3.6.1 84 If ``Py_LIMITED_API`` is set to the value less than ``0x03050400`` or 85 between ``0x03060000`` and ``0x03060100`` (not including) 86 :c:func:`!PySlice_GetIndicesEx` is a deprecated function. 87 88 89.. c:function:: int PySlice_Unpack(PyObject *slice, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step) 90 91 Extract the start, stop and step data members from a slice object as 92 C integers. Silently reduce values larger than ``PY_SSIZE_T_MAX`` to 93 ``PY_SSIZE_T_MAX``, silently boost the start and stop values less than 94 ``PY_SSIZE_T_MIN`` to ``PY_SSIZE_T_MIN``, and silently boost the step 95 values less than ``-PY_SSIZE_T_MAX`` to ``-PY_SSIZE_T_MAX``. 96 97 Return ``-1`` on error, ``0`` on success. 98 99 .. versionadded:: 3.6.1 100 101 102.. c:function:: Py_ssize_t PySlice_AdjustIndices(Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t step) 103 104 Adjust start/end slice indices assuming a sequence of the specified length. 105 Out of bounds indices are clipped in a manner consistent with the handling 106 of normal slices. 107 108 Return the length of the slice. Always successful. Doesn't call Python 109 code. 110 111 .. versionadded:: 3.6.1 112 113 114Ellipsis Object 115--------------- 116 117 118.. c:var:: PyObject *Py_Ellipsis 119 120 The Python ``Ellipsis`` object. This object has no methods. It needs to be 121 treated just like any other object with respect to reference counts. Like 122 :c:data:`Py_None` it is a singleton object. 123