I am hoping to downsample the dataset with uneven sub-hour intervals to 6-hourly, with fixed time points of 00H, 6H, 12H and 18H. If data at these time points exist, keep. If not, use the observation from the nearest previous datapoint without data manipulation, keeping original records.
import pandas as pddata = pd.DataFrame({'dt': ['2022-10-29 18:00:00', '2022-10-30 00:00:00','2022-10-30 06:00:00', '2022-10-30 12:00:00','2022-10-30 18:00:00', '2022-10-31 00:00:00','2022-10-31 06:00:00', '2022-10-31 12:00:00','2022-10-31 15:00:00', '2022-10-31 15:30:00','2022-10-31 16:00:00', '2022-10-31 16:30:00','2022-10-31 17:00:00', '2022-10-31 17:30:00','2022-10-31 18:00:00', '2022-10-31 18:30:00','2022-10-31 19:00:00', '2022-10-31 19:30:00','2022-10-31 20:00:00', '2022-10-31 20:30:00','2022-10-31 21:00:00', '2022-10-31 21:30:00','2022-10-31 22:00:00', '2022-10-31 22:30:00','2022-10-31 23:00:00', '2022-10-31 23:30:00','2022-11-01 00:00:00', '2022-11-01 00:30:00','2022-11-01 01:00:00', '2022-11-01 01:30:00','2022-11-01 02:00:00', '2022-11-01 02:30:00','2022-11-01 03:00:00', '2022-11-01 03:30:00','2022-11-01 04:00:00', '2022-11-01 04:30:00','2022-11-01 05:00:00', '2022-11-01 05:30:00','2022-11-01 06:00:00', '2022-11-01 06:30:00','2022-11-01 07:00:00', '2022-11-01 07:30:00','2022-11-01 08:00:00', '2022-11-01 08:30:00','2022-11-01 09:00:00', '2022-11-01 09:30:00','2022-11-01 10:00:00', '2022-11-01 10:30:00','2022-11-01 11:00:00', '2022-11-01 11:30:00'],'Value': [ 8786.8, 8789.5, 8787.7, 8789.2, 8789.4, 8790.3, 8789.6, 8790.5, 8789.7, 8790.6, 8790.5, 8790.5, 8790.4, 8790.4, 8790.3, 8790.2, 8790.1, 8790.0, 8789.9, 8789.8, 8789.7, 8789.5, 8789.5, 8789.3, 8789.2, 8789.6, 8789.8, 8789.8, 8789.7, 8789.6, 8789.7, 8789.5, 8789.5, 8789.3, 8789.2, 8789.6, 8789.8, 8789.8, 8789.7, 8789.6, 8789.7, 8789.6, 8789.5, 8789.3, 8789.2, 8789.6, 8789.8, 8789.8, 8789.7, 8789.6]})data.index = pd.DatetimeIndex(data['dt'])But with data.resample('6H').last(), strangely I get one data point at 17:30 instead of 18:00 starting at 2022-10-31:
