I want to remove data from my dataframe older than say 2 hours from current time starting with 00 mins (datetime column is in index)
when i use below code
df = df[df.index > df.index.max() - pd.Timedelta(hours=2)]
| datetime | value | |---------------------|-------| | 17-03-2022 15:05:00 | 78 | | 17-03-2022 15:07:00 | 86 | | 17-03-2022 15:57:00 | 77 | | 17-03-2022 15:58:00 | 22 | | 17-03-2022 15:59:00 | 10 | | 17-03-2022 16:00:00 | 22 | | 17-03-2022 16:01:00 | 25 | | 17-03-2022 16:02:00 | 25 | | 17-03-2022 17:05:00 | 34 |
Current datetime: ’17-03-2022 17:05:00′
Issue: My code keeps all records in df from ’17-03-2022 15:05:00′ to ’17-03-2022 17:05:00′
Requirement: All records in df from ’17-03-2022 15:00:00′ to ’17-03-2022 17:05:00′
It should start from 00th minute of -2hrs
| datetime | value | |---------------------|-------| | 17-03-2022 15:00:00 | 18 | | 17-03-2022 15:05:00 | 78 | | 17-03-2022 15:07:00 | 86 | | 17-03-2022 15:57:00 | 77 | | 17-03-2022 15:58:00 | 22 | | 17-03-2022 15:59:00 | 10 | | 17-03-2022 16:00:00 | 22 | | 17-03-2022 16:01:00 | 25 | | 17-03-2022 16:02:00 | 25 | | 17-03-2022 17:05:00 | 34 |
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Answer
Use Timestamp.floor with change > to >=:
df = df[df.index >= (df.index.max() - pd.Timedelta(hours=2)).floor('H')]
print (df)
value
datetime
2022-03-17 15:00:00 18
2022-03-17 15:05:00 78
2022-03-17 15:07:00 86
2022-03-17 15:57:00 77
2022-03-17 15:58:00 22
2022-03-17 15:59:00 10
2022-03-17 16:00:00 22
2022-03-17 16:01:00 25
2022-03-17 16:02:00 25
2022-03-17 17:05:00 34