Pandas groupby max - 多列

Question

在pandas中分组到最大值后，如何将匹配的行结果完全沿max()值显示

df = data.loc[:,['no','std_date','result_date','result']]
result = df.groupby(['no','std_date'])[['result_date','result']].max()

我在每个“std_date”上显示结果并发送结果。但是，现在 'result_date' 和 'result' 的每一列的最大值。 enter image description here

我的数据:

    no  std_date    result_date result
0   s1  2012-12-24  2012-07-03  601.19
1   s2  2011-11-23  2011-05-16  1.96
2   s2  2011-11-23  2011-11-10  15.2
3   s3  2016-08-10  2016-04-23  14.05
4   s5  2013-11-12  2013-05-31  34.73
5   s5  2013-11-12  2013-07-22  12
6   s5  2017-11-14  2014-05-09  0.59
7   s5  2017-11-14  2016-09-07  0.8
8   s5  2017-11-14  2017-06-20  1.54
9   s6  2012-06-01  2012-05-14  1.08
10  s7  2018-11-19  2018-04-10  25.74
11  s7  2018-11-19  2018-10-16  12.49
12  s8  2013-12-24  2013-10-17  26.48
13  s8  2016-01-20  2013-12-31  1.36
14  s8  2016-01-20  2014-08-27  0.9
15  s8  2016-01-20  2015-06-29  3.72

我要:

                   result_date  result
no  std_date        
s1  2012-12-24  2012-11-28  601.19
s2  2011-11-23  2011-11-10  15.2
s3  2016-08-10  2016-04-23  14.05
s5  2013-11-12  2013-07-22  12
s5  2017-11-14  2017-06-20  1.54
s6  2012-06-01  2012-05-14  1.08
s7  2018-11-19  2018-10-16  12.49
s8  2013-12-24  2013-10-17  26.48
s8  2016-01-20  2015-06-29  3.72

Answer 1

您可以保留结果，然后将其合并回 DataFrame

result = df.groupby(['no','std_date'])[['result_date']]\
    .max()\
    .reset_index()\
    .merge(df,on=['no','std_date','result_date'])

输出:

   no  std_date result_date  result
0  s1  12-12-24    12-07-03  601.19
1  s2  11-11-23    11-11-10   15.20
2  s3  16-08-10    16-04-23   14.05
3  s5  13-11-12    13-07-22   12.00
4  s5  17-11-14    17-06-20    1.54
5  s6  12-06-01    12-05-14    1.08
6  s7  18-11-19    18-10-16   12.49
7  s8  13-12-24    13-10-17   26.48
8  s8  16-01-20    15-06-29    3.72