Fix DataFrame.select when no set index (#613)

* Fix DataFrame.select when no set index

* Remove dead code

* Add test

* Fix MeshIndex.values evaluation

* Fix MeshIndex.values evaluation

src/ansys/dpf/post/dataframe.py

@@ -352,15 +352,14 @@ def select(self, **kwargs) -> DataFrame:
             indexes=row_indexes,
         )
 
+        set_index = None
         if "time" in fc.labels:
             set_index = SetIndex(values=fc.get_available_ids_for_label("time"))
-        else:
-            set_index = SetIndex(values=[])
 
-        column_indexes = [
-            results_index,
-            set_index,
-        ]
+        column_indexes = [results_index]
+        if set_index:
+            column_indexes.append(set_index)
+
         if isinstance(fc, PropertyFieldsContainer):
             column_indexes = [results_index]
 

src/ansys/dpf/post/index.py

@@ -152,7 +152,7 @@ def __init__(
 
     def _evaluate_values(self):
         """Evaluates the values of the MeshIndex."""
-        if self._scoping_ref is not None:
+        if self._scoping_ref is not None and self._scoping_ref() is not None:
             self._values = self._scoping_ref().ids
         else:
             # Merge the fields container scoping

tests/test_dataframe.py

@@ -116,6 +116,15 @@ def test_dataframe_select(df):
     # print(df2)
 
 
+def test_dataframe_select_no_set_index():
+    simulation = post.StaticMechanicalSimulation(examples.find_simple_bar())
+    df = simulation.mesh.coordinates
+    df2 = df.select(components="X")
+    assert len(df2.index) == 2
+    assert df2.index.components.values == ["X"]
+    assert len(df2.mesh_index.values) == len(df.mesh_index.values)
+
+
 @pytest.mark.skipif(
     not SERVERS_VERSION_GREATER_THAN_OR_EQUAL_TO_7_0,
     reason="Fluid capabilities added with ansys-dpf-server 2024.1.pre0.",