Pandas BUG: resample on empty DataFrame leads to ValueError

Before version 2.0.0 I was able to resample an empty DataFrame with DateTimeIndex. Now it leads to a ValueError. Is that on purpose or a bug?

Comment From: MarcoGorelli

can you show a reproducible example please?

Comment From: ASchueddekopf

If you create a python file with the following code it will result in a df with 15 min frequency datetimeIndex with pandas version 1.5.2 and a value error with pandas 2.0.0:

import datetime
import pandas as pd

def main():
    year = 2018
    freq = "1H"

    index = pd.date_range(
            start=datetime.datetime(year, 1, 1),
            end=datetime.datetime(year + 1, 1, 1),
            freq=freq,
        )
    index = index[:-1]
    index = pd.to_datetime(index)

    df = pd.DataFrame(index=index)
    df.resample("15Min").mean()

if __name__ == "__main__":
    main()

Comment From: MarcoGorelli

thanks

looks like this was introduced by https://github.com/pandas-dev/pandas/pull/47672 cc @mroeschke @rhshadrach @ahmedibrhm

https://www.kaggle.com/code/marcogorelli/pandas-regression-example/notebook?scriptVersionId=125373741