我如何计算人口最多的县的总和？

Question

仅看每个州人口最多的两个县，人口最多的两个州是什么（按人口最高到人口最低的顺序）

State          County          Population
Dhaka          Dhaka city      120000
               Narayanganj     50000
               Gazipur         40000
Rangpur        Gaibandha       36000
               Rangpur city    54000
               Lalmonirhat     68000
Rajshahi       Rajshahi city   98500
               Bogura          56000
               Naogaon         16000

Answer 1

使用nlargest

df.groupby(['State'])['Population'].nlargest(2).groupby(level=0).sum()

State
Dhaka       170000
Rajshahi    154500
Rangpur     122000
Name: Population, dtype: int64