code sample for pandas-dev#42747

Author: simonjayhawkins

bisect/42747.py

@@ -0,0 +1,13 @@
+# BUG: freq attribute is None after set_index #42747
+
+import numpy as np
+import pandas as pd
+
+print(pd.__version__)
+
+df = pd.DataFrame({"datetime": pd.date_range("1/1/1", periods=20, freq="H", tz="UTC")})
+df.set_index("datetime", inplace=True)
+
+result = df.index.freq
+print(result)
+assert result == "H", result