python - Calculating a rolling window of 8 hour size, using half hour increments in pandas

Question

I have a data frame with the following date column:

	scheduled_departure_utc	run_id
0	2021-01-11 13:07:00+00:00	13149
128	2021-01-11 13:07:00+00:00	38138
1	2021-01-11 13:37:00+00:00	13153
129	2021-01-11 13:37:00+00:00	38139
2	2021-01-11 18:07:00+00:00	951600
130	2021-01-11 18:07:00+00:00	951600
3	2021-01-11 18:22:00+00:00	951780
131	2021-01-11 18:22:00+00:00	951780
132	2021-01-11 18:26:00+00:00	951201
4	2021-01-11 18:37:00+00:00	951802

Answer 1

One way would be to first resample the dataframe to have the same frequency as your wanted step-size (in this case 30 minutes). Then you can use rolling with a window size of 16 (i.e., 8 hours).

df['scheduled_departure_utc'] = pd.to_datetime(df['scheduled_departure_utc'])
df.set_index('scheduled_departure_utc').resample('30T').count()['run_id'].rolling(window=16, min_periods=1).sum()

Resulting pandas series:

2021-01-11 13:00:00     2.0
2021-01-11 13:30:00     4.0
2021-01-11 14:00:00     4.0
2021-01-11 14:30:00     4.0
2021-01-11 15:00:00     4.0
2021-01-11 15:30:00     4.0
2021-01-11 16:00:00     4.0
2021-01-11 16:30:00     4.0
2021-01-11 17:00:00     4.0
2021-01-11 17:30:00     4.0
2021-01-11 18:00:00     9.0
2021-01-11 18:30:00    10.0