diff --git a/python/pyarrow/array.pxi b/python/pyarrow/array.pxi index 7d9b65c77d25a..def4c5e9ba962 100644 --- a/python/pyarrow/array.pxi +++ b/python/pyarrow/array.pxi @@ -549,32 +549,36 @@ def _normalize_slice(object arrow_obj, slice key): Py_ssize_t start, stop, step Py_ssize_t n = len(arrow_obj) - start = key.start or 0 - if start < 0: - start += n + step = key.step or 1 + + if key.start is None: + if step < 0: + start = n - 1 + else: + start = 0 + elif key.start < 0: + start = key.start + n if start < 0: start = 0 - elif start >= n: + elif key.start >= n: start = n + else: + start = key.start - stop = key.stop if key.stop is not None else n - if stop < 0: - stop += n - if stop < 0: + if step < 0 and (key.stop is None or key.stop < -n): + stop = -1 + elif key.stop is None: + stop = n + elif key.stop < 0: + stop = key.stop + n + if stop < 0: # step > 0 in this case. stop = 0 - elif stop >= n: + elif key.stop >= n: stop = n + else: + stop = key.stop - step = key.step or 1 if step != 1: - if step < 0: - # Negative steps require some special handling - if key.start is None: - start = n - 1 - - if key.stop is None: - stop = -1 - indices = np.arange(start, stop, step) return arrow_obj.take(indices) else: diff --git a/python/pyarrow/tests/test_array.py b/python/pyarrow/tests/test_array.py index 782c41d0d7015..a8cd20720e437 100644 --- a/python/pyarrow/tests/test_array.py +++ b/python/pyarrow/tests/test_array.py @@ -485,6 +485,7 @@ def test_array_slice_negative_step(): slice(10, 2, -2), slice(None, None, 2), slice(0, 10, 2), + slice(15, -25, -1), # GH-38768 ] for case in cases: