code sample for pandas-dev#46375

Author: simonjayhawkins

bisect/46375.py

@@ -0,0 +1,12 @@
+# BUG: DataFrameGroupBy.sum() drops column names when applied to an empty dataframe #46375
+
+import pandas as pd
+
+print(pd.__version__)
+
+df = pd.DataFrame(columns=["a", "b", "c"])
+result = df.groupby("a", as_index=False).sum()
+print(result)
+
+expected = pd.Index(["a", "b", "c"], dtype="object")
+pd.testing.assert_index_equal(result.columns, expected)