แต่ละทวีปมีผู้ผลิตรถยนต์กี่ราย? ระบุชื่อทวีปและจำนวน
How many car makers are there in each continents? List the continent name and the count.
countries = pd.DataFrame({'continent': list_of_continent_ids, 'CountryId': list_of_country_ids}); continents = pd.DataFrame({'Continent': list_of_continent_names, 'ContId': list_of_continent_ids}); car_makers = pd.DataFrame({'Country': list_of_country_ids})
car_makers['Country'].value_counts().to_frame().merge(countries, left_index=True, right_on='CountryId').merge(continents, left_on='continent', right_on='ContId')[['Continent', 'Country']]