Add python bindings for Frame::getName (#608)

python/podio/frame.py

@@ -107,6 +107,32 @@ def get(self, name):
             raise KeyError(f"Collection '{name}' is not available")
         return collection
 
+    def getName(self, token):
+        """Get the name of the collection from the Frame
+
+        Args:
+            token (podio.CollectionBase | int): A collection or its ID
+
+        Returns:
+            str: The name of the collection inside the frame
+
+        Raises:
+            KeyError: If no collection can be found in the frame
+
+        """
+        maybeName = self._frame.getName(token)
+        if maybeName.has_value():
+            return maybeName.value()
+
+        def _get_id(tok):
+            if isinstance(tok, int):
+                return f"{tok:0>8x}"
+            return _get_id(tok.getID())
+
+        raise KeyError(
+            f"No collection name can be found in Frame for collection id: {_get_id(token)}"
+        )
+
     def put(self, collection, name):
         """Put the collection into the frame
 

python/podio/test_Frame.py

@@ -70,6 +70,17 @@ def test_frame_invalid_access(self):
             collection = [1, 2, 4]
             _ = frame.put(collection, "invalid_collection_type")
 
+    def test_frame_get_name_invalid_token(self):
+        """Check that trying to get the collection name raises an exception if
+        the collection is not known to the frame"""
+        frame = Frame()
+        with self.assertRaises(KeyError):
+            _ = frame.getName(42)
+
+        with self.assertRaises(KeyError):
+            coll = ExampleHitCollection()
+            _ = frame.getName(coll)
+
     def test_frame_put_collection(self):
         """Check that putting a collection works as expected"""
         frame = Frame()
@@ -195,3 +206,9 @@ def test_frame_parameters(self):
         )
         # as_type='float' will also retrieve double values (if the name is unambiguous)
         self.assertEqual(self.event.get_parameter("SomeVectorData", as_type="float"), [0.0, 0.0])
+
+    def test_frame_get_name(self):
+        """Check that retrieving the name of a collection works as expected"""
+        mc_particles = self.event.get("mcparticles")
+        self.assertEqual(self.event.getName(mc_particles), "mcparticles")
+        self.assertEqual(self.event.getName(mc_particles.getID()), "mcparticles")