更新时间:2022-12-10 16:29:40
print (df)
PERIOD_START_TIME ID A VALUE
0 06.01.2017 02:00:00 55 8 35
1 06.01.2017 02:00:00 55 8 22
2 06.01.2017 03:00:00 55 8 63
3 06.01.2017 03:00:00 55 8 33
4 06.01.2017 04:00:00 55 8 63
5 06.01.2017 04:00:00 55 8 45
6 06.01.2017 02:00:00 65 8 10
7 06.01.2017 02:00:00 65 8 5
8 06.01.2017 03:00:00 65 8 22
9 06.01.2017 03:00:00 65 8 5
10 06.01.2017 04:00:00 65 8 12
11 06.01.2017 04:00:00 65 8 15
df = df.groupby(['PERIOD_START_TIME','ID'], as_index=False)['VALUE'].max()
或者:
df = df.groupby(['PERIOD_START_TIME','ID'])['VALUE'].max().reset_index()
print (df)
PERIOD_START_TIME ID VALUE
0 06.01.2017 02:00:00 55 35
1 06.01.2017 02:00:00 65 10
2 06.01.2017 03:00:00 55 63
3 06.01.2017 03:00:00 65 22
4 06.01.2017 04:00:00 55 63
5 06.01.2017 04:00:00 65 15
For more columns need idxmax
and select by loc
:
df = df.loc[df.groupby(['PERIOD_START_TIME','ID'])['VALUE'].idxmax()]
print (df)
PERIOD_START_TIME ID A VALUE
0 06.01.2017 02:00:00 55 8 35
6 06.01.2017 02:00:00 65 8 10
2 06.01.2017 03:00:00 55 8 63
8 06.01.2017 03:00:00 65 8 22
4 06.01.2017 04:00:00 55 8 63
11 06.01.2017 04:00:00 65 8 15
替代方案:
cols = ['PERIOD_START_TIME','ID']
df = df.sort_values(cols).groupby(cols, as_index=False).first()
print (df)
PERIOD_START_TIME ID A VALUE
0 06.01.2017 02:00:00 55 8 35
1 06.01.2017 02:00:00 65 8 10
2 06.01.2017 03:00:00 55 8 63
3 06.01.2017 03:00:00 65 8 22
4 06.01.2017 04:00:00 55 8 63
5 06.01.2017 04:00:00 65 8 12