Merge pull request #4754 from voxel51/bug/group-by-match

Fix bug with group_by(..., match_expr=)
voxel51 · Aug 30, 2024 · f8b89e8 · f8b89e8
2 parents dbdda14 + 76e4192
commit f8b89e8
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diff --git a/fiftyone/core/stages.py b/fiftyone/core/stages.py
@@ -3416,7 +3416,7 @@ def _make_flat_pipeline(self, sample_collection):
         )
 
         if match_expr is not None:
-            pipeline.append({"$match": match_expr})
+            pipeline.append({"$match": {"$expr": match_expr}})
 
         if sort_expr is not None:
             order = -1 if self._reverse else 1

diff --git a/tests/unittests/group_tests.py b/tests/unittests/group_tests.py
@@ -1978,6 +1978,15 @@ def test_flatten(self):
         )
         self.assertListEqual(view.values("frame_number"), [1, 1])
 
+    @drop_datasets
+    def test_match_expr(self):
+        dataset = _make_group_by_dataset()
+
+        view = dataset.group_by(
+            "frame_number", flat=True, match_expr=(F().length() > 1)
+        )
+        self.assertDictEqual(view.count_values("frame_number"), {1: 2, 2: 2})
+
     @drop_datasets
     def test_group_by_group_dataset(self):
         dataset = _make_group_by_group_dataset()