Finding hour of daily max using Pandas in Python
UPDATE from 2018-09-19:
FutureWarning: pd.TimeGrouper is deprecated and will be removed; Please use pd.Grouper(freq=...)
solution:
In [295]: df.loc[df.groupby(pd.Grouper(freq='D')).idxmax().iloc[:, 0]]
Out[295]:
power
2011-01-01 06:00:00 1054.6
2011-01-02 06:00:00 2054.6
Old answer:
try this:
In [376]: df.loc[df.groupby(pd.TimeGrouper('D')).idxmax().iloc[:, 0]]
Out[376]:
power
2011-01-01 06:00:00 1054.6
2011-01-02 06:00:00 2054.6
data:
In [377]: df
Out[377]:
power
2011-01-01 00:00:00 1015.7
2011-01-01 01:00:00 1015.7
2011-01-01 02:00:00 1010.3
2011-01-01 03:00:00 1010.9
2011-01-01 04:00:00 1021.1
2011-01-01 05:00:00 1046.0
2011-01-01 06:00:00 1054.6
2011-01-02 00:00:00 2015.7
2011-01-02 01:00:00 2015.7
2011-01-02 02:00:00 2010.3
2011-01-02 03:00:00 2010.9
2011-01-02 04:00:00 2021.1
2011-01-02 05:00:00 2046.0
2011-01-02 06:00:00 2054.6