python - Pandas function operations

Question

Data is from the United States Census Bureau. Counties are political and geographic subdivisions of states in the United States. This dataset contains population data for counties and states in the US from 2010 to 2015.

Which state has the most counties in it? (hint: consider the sumlevel key carefully! You'll need this for future questions too...)

I can not fetch the county name out of the code. Please help

my code:

import pandas as pd
import numpy as np
census_df = pd.read_csv('census.csv')
census_df.head()
def answer_five():
    return census_df.groupby('STNAME').COUNTY.sum().max()



answer_five()

Answer 1

Here is the answer that worked for me:

def answer_five():
    return census_df.groupby(["STNAME"],sort=False).sum()["COUNTY"].idxmax()

First part created aggregated df

census_df.groupby(["STNAME"],sort=False).sum()

Second part takes the col you need

["COUNTY"].idxmax()

and returns value corresponding to index with max, check here