切片对象

PyTypeObject PySlice_Type

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.

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(PyObject *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.

在 3.2 版更改: 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)

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.

注解

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);

在 3.2 版更改: The parameter type for the slice parameter was PySliceObject* before.

在 3.6.1 版更改: 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.

3.6.1 版后已移除: 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)

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 on error, 0 on success.

3.6.1 新版功能.

Py_ssize_t PySlice_AdjustIndices(Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t step)

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.

3.6.1 新版功能.

Ellipsis Object

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.