map ordinal day to day of year

python/cudf_polars/cudf_polars/dsl/expressions/datetime.py

@@ -116,7 +116,10 @@ def __init__(
         self.name = name
         self.children = children
         self.is_pointwise = True
-        if self.name not in self._COMPONENT_MAP:
+        if (
+            self.name not in self._COMPONENT_MAP
+            and self.name is not self.Name.OrdinalDay
+        ):
             raise NotImplementedError(f"Temporal function {self.name}")
 
     def do_evaluate(
@@ -132,6 +135,8 @@ def do_evaluate(
             for child in self.children
         ]
         (column,) = columns
+        if self.name is TemporalFunction.Name.OrdinalDay:
+            return Column(plc.datetime.day_of_year(column.obj))
         if self.name is TemporalFunction.Name.Microsecond:
             millis = plc.datetime.extract_datetime_component(
                 column.obj, plc.datetime.DatetimeComponent.MILLISECOND

python/cudf_polars/tests/expressions/test_datetime_basic.py

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright (c) 2024 NVIDIA CORPORATION & AFFILIATES.
+# SPDX-FileCopyrightText: Copyright (c) 2024-2025, NVIDIA CORPORATION & AFFILIATES.
 # SPDX-License-Identifier: Apache-2.0
 from __future__ import annotations
 
@@ -135,3 +135,23 @@ def test_date_extract(field):
     q = ldf.select(field(pl.col("dates").dt))
 
     assert_gpu_result_equal(q)
+
+
+@pytest.mark.parametrize(
+    "start_date, end_date",
+    [
+        (datetime.date(2001, 12, 22), datetime.date(2001, 12, 25)),
+        (datetime.date(2000, 2, 27), datetime.date(2000, 3, 1)),  # Leap year transition
+        (datetime.date(1999, 12, 31), datetime.date(2000, 1, 2)),
+        (datetime.date(2020, 2, 28), datetime.date(2020, 3, 1)),
+        (datetime.date(2021, 1, 1), datetime.date(2021, 1, 2)),
+    ],
+)
+def test_ordinal_day(start_date, end_date):
+    df = pl.DataFrame({"date": pl.date_range(start_date, end_date, eager=True)}).lazy()
+
+    q = df.with_columns(
+        pl.col("date").dt.ordinal_day().alias("day_of_year"),
+    )
+
+    assert_gpu_result_equal(q)