pandas實現分組排序

import pandas as pd

df = pd.DataFrame([['A',1,'2019-03-01 00:00:30'],
                  ['A',3,'2019-04-01 00:00:30'],
                  ['A',2,'2019-03-01 00:00:30'],
                  ['B',5,'2019-03-01 00:00:30'],
                  ['B',9,'2019-03-01 00:00:29']],
                  columns = ['name','score','tm'])
 
 df.sort_values(['name','tm'], ascending = [False,True], inplace=True)