I just started to use Python and Pandas. My current solution to a problem looks ugly and inefficient. I would like to know how to improve it. Data file is Census 2010 can be viewed hereQuestion:Only looking at the three most populous counties for each state, what are the three most populous states (in order of highest population to lowest population)? Use CENSUS2010POP.  This function should return a list of string values.Current codedef answer_six():    cdf = census_df[census_df['SUMLEV'] == 50]    cdf = cdf.groupby('STNAME')    cdf = cdf.apply(lambda x:x.sort_values('CENSUS2010POP', ascending=False)).reset_index(drop=True)    cdf = cdf.groupby('STNAME').head(3)    cdf = cdf.groupby('STNAME').sum()    cdf = cdf.sort_values('CENSUS2010POP', axis=0, ascending=False).head(3)    return list(cdf.index)
Finding the states with the three most populous counties
python;performance;beginner;csv;pandas