[英]Pandas group by with multiple columns and max value
I have some problems with group by
with multiple columns and max
value. 我有多个列和max
group by
问题。
A B C D E F G H
x q e m k 2 1 y
x q e n l 5 2 y
x w e b j 7 3 y
x w e v h 3 4 y
This query is correct and returning what I want. 此查询是正确的,并返回我想要的。
SELECT A, B, C, D, E, MAX(F) FROM mytable group by A, B, C
Results 结果
x q e n l 5
x w e b j 7
How it can be achieved in pandas? 如何在大熊猫中实现?
I try this: 我尝试这样:
df.groupby(['A', 'B', 'C'], as_index=False)['F'].max()
And this translates to this: 这就是这样:
SELECT A, B, C, MAX(F) FROM mytable group by A, B, C
This also does not work 这也行不通
df.groupby(['A', 'B', 'C'], as_index=False)['F','D','E'].max()
How can I return also column D, E as it in sql query? 如何在SQL查询中也返回D,E列?
Seems like you need 好像你需要
groups = ['A', 'B', 'C']
selects = ['A', 'B', 'C','D', 'E','F']
df.groupby(groups, as_index=False).apply(lambda s: s.loc[s.F.idxmax(), selects]).reset_index(drop=True)
A B C D E F
0 x q e n l 5
1 x w e b j 7
尝试这样的事情:
df.groupby(['A', 'B', 'C'], as_index=False).agg({'D': 'first', 'E': 'last', 'F': 'max'})
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