Groupby 2 个不同的列 Python Pandas

Question

import pandas as pd

df1 = pd.DataFrame([['Dog', '2017', 100], ['Dog', '2017' ,500],['Dog', '2016' ,200],['Dog', '2016' ,150],['Cat', '2017' ,50],['Cat', '2017' ,100],
['Cat', '2016' ,50]], columns=('Pet','Year','Amount'))

DF1

Pet  Year  Amount
Dog  2017  100
Dog  2017  500
Dog  2016  200
Dog  2016  150
Cat  2017  50
Cat  2017  100
Cat  2016  50

我想将上面的数据框变成以下内容：

DF2

Pet Year Amount
Dog 2017 600
Dog 2016 350
Cat 2017 150
Cat 2016 50

这是按宠物和按年份分组，并汇总它们之间的数量。

有任何想法吗？

Answer 1

使用带参数as_index=False groupby不返回MultiIndex和sort=False避免排序：

print (df1.groupby(['Pet','Year'], as_index=False, sort=False).sum())
   Pet  Year  Amount
0  Dog  2017     600
1  Dog  2016     350
2  Cat  2017     150
3  Cat  2016      50