From ee3e9fe2f2279e5ad80b5ea1399bb7d9e9d0006e Mon Sep 17 00:00:00 2001
From: Matthew Murray <matthewmurray711@gmail.com>
Date: Tue, 2 Jul 2024 14:59:14 -0700
Subject: [PATCH 1/2] Initial commit

---
 .../_lib/pylibcudf/libcudf/lists/reverse.pxd  | 14 ++++++++++
 python/cudf/cudf/_lib/pylibcudf/lists.pxd     |  2 ++
 python/cudf/cudf/_lib/pylibcudf/lists.pyx     | 26 +++++++++++++++++++
 .../cudf/cudf/pylibcudf_tests/test_lists.py   | 12 +++++++++
 4 files changed, 54 insertions(+)
 create mode 100644 python/cudf/cudf/_lib/pylibcudf/libcudf/lists/reverse.pxd

diff --git a/python/cudf/cudf/_lib/pylibcudf/libcudf/lists/reverse.pxd b/python/cudf/cudf/_lib/pylibcudf/libcudf/lists/reverse.pxd
new file mode 100644
index 00000000000..1e1dc4c46b5
--- /dev/null
+++ b/python/cudf/cudf/_lib/pylibcudf/libcudf/lists/reverse.pxd
@@ -0,0 +1,14 @@
+# Copyright (c) 2021-2024, NVIDIA CORPORATION.
+
+from libcpp.memory cimport unique_ptr
+
+from cudf._lib.pylibcudf.libcudf.column.column cimport column
+from cudf._lib.pylibcudf.libcudf.lists.lists_column_view cimport (
+    lists_column_view,
+)
+
+
+cdef extern from "cudf/lists/reverse.hpp" namespace "cudf::lists" nogil:
+    cdef unique_ptr[column] reverse(
+        const lists_column_view& lists_column,
+    ) except +
diff --git a/python/cudf/cudf/_lib/pylibcudf/lists.pxd b/python/cudf/cudf/_lib/pylibcudf/lists.pxd
index 2ccf0139e90..c9d0a84e8ac 100644
--- a/python/cudf/cudf/_lib/pylibcudf/lists.pxd
+++ b/python/cudf/cudf/_lib/pylibcudf/lists.pxd
@@ -23,3 +23,5 @@ cpdef Column contains(Column, ColumnOrScalar)
 cpdef Column contains_nulls(Column)
 
 cpdef Column index_of(Column, ColumnOrScalar, bool)
+
+cpdef Column reverse(Column)
diff --git a/python/cudf/cudf/_lib/pylibcudf/lists.pyx b/python/cudf/cudf/_lib/pylibcudf/lists.pyx
index a94d940accd..651f1346f88 100644
--- a/python/cudf/cudf/_lib/pylibcudf/lists.pyx
+++ b/python/cudf/cudf/_lib/pylibcudf/lists.pyx
@@ -9,6 +9,7 @@ from cudf._lib.pylibcudf.libcudf.column.column cimport column
 from cudf._lib.pylibcudf.libcudf.lists cimport (
     contains as cpp_contains,
     explode as cpp_explode,
+    reverse as cpp_reverse,
 )
 from cudf._lib.pylibcudf.libcudf.lists.combine cimport (
     concatenate_list_elements as cpp_concatenate_list_elements,
@@ -206,3 +207,28 @@ cpdef Column index_of(Column input, ColumnOrScalar search_key, bool find_first_o
             find_option,
         ))
     return Column.from_libcudf(move(c_result))
+
+
+cpdef Column reverse(Column input):
+    """Reverse the element order within each list of the input column.
+
+    For details, see :cpp:func:`reverse`.
+
+    Parameters
+    ----------
+    input : Column
+        The input column.
+
+    Returns
+    -------
+    Column
+        A new Column with reversed lists.
+    """
+    cdef unique_ptr[column] c_result
+    cdef ListColumnView list_view = input.list_view()
+
+    with nogil:
+        c_result = move(cpp_reverse.reverse(
+            list_view.view(),
+        ))
+    return Column.from_libcudf(move(c_result))
diff --git a/python/cudf/cudf/pylibcudf_tests/test_lists.py b/python/cudf/cudf/pylibcudf_tests/test_lists.py
index c781126e388..58a1dcf8d56 100644
--- a/python/cudf/cudf/pylibcudf_tests/test_lists.py
+++ b/python/cudf/cudf/pylibcudf_tests/test_lists.py
@@ -134,3 +134,15 @@ def test_index_of_list_column(test_data, column):
     expect = pa.array(column[1], type=pa.int32())
 
     assert_column_eq(expect, res)
+
+
+def test_reverse(test_data):
+    list_column = test_data[0][0]
+    arr = pa.array(list_column)
+    plc_column = plc.interop.from_arrow(arr)
+
+    res = plc.lists.reverse(plc_column)
+
+    expect = pa.array([lst[::-1] for lst in list_column])
+
+    assert_column_eq(expect, res)

From de769037747728866950d4682aefefe0c7b38f20 Mon Sep 17 00:00:00 2001
From: Lawrence Mitchell <wence@gmx.li>
Date: Thu, 4 Jul 2024 16:39:49 +0100
Subject: [PATCH 2/2] Correct copyright date

---
 python/cudf/cudf/_lib/pylibcudf/libcudf/lists/reverse.pxd | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/python/cudf/cudf/_lib/pylibcudf/libcudf/lists/reverse.pxd b/python/cudf/cudf/_lib/pylibcudf/libcudf/lists/reverse.pxd
index 1e1dc4c46b5..0382a5d42c3 100644
--- a/python/cudf/cudf/_lib/pylibcudf/libcudf/lists/reverse.pxd
+++ b/python/cudf/cudf/_lib/pylibcudf/libcudf/lists/reverse.pxd
@@ -1,4 +1,4 @@
-# Copyright (c) 2021-2024, NVIDIA CORPORATION.
+# Copyright (c) 2024, NVIDIA CORPORATION.
 
 from libcpp.memory cimport unique_ptr