pandas groupby 聚合函数中重复最多的字符串

Question

I have a data like this

Customer ID	Amount	Location
1	2500	India
2	3000	USA
1	1000	India
2	500	India
1	2500	India
1	500	USA
2	500	USA

How can I use groupby aggregate function in pandas to return the sum of Amount column and most repeated string in Location column on customer level:

Customer ID	Amount	Location
1	5500	India
2	400	USA

Answer 1

Use GroupBy.agg with aggregate functions, for Series.mode is necessary add iat[0] for get first value if multiple top values:

df.groupby('Customer ID').agg({'Amount':'sum', 'Location': lambda x: x.mode().iat[0]})