code sample for pandas-dev#43767

Author: simonjayhawkins

bisect/43767.py

@@ -0,0 +1,15 @@
+# BUG: reset_index after a group_by raise a ValueError for empty dataframe #43767
+
+import datetime as dt
+
+import pandas as pd
+
+print(pd.__version__)
+
+df = pd.DataFrame([(dt.date.today(), "b", 12)], columns=["date", "b", "count"])
+df["date"] = pd.to_datetime(df["date"])
+df = df[
+    df["count"] == 1
+]  # uncomment this line to make the dataframe empty and so reset_index raising an exception
+result = df.set_index("date").groupby(["b"]).resample("M").sum().reset_index()
+print(result)