“ลินดา สมิธ” อยู่กี่สโมสร?
How many clubs does "Linda Smith" belong to?
student = pd.DataFrame(columns=['stuid', 'fname', 'lname']); member_of_club = pd.DataFrame(columns=['clubid', 'stuid']); club = pd.DataFrame(columns=['clubid'])
member_of_club[member_of_club['stuid'].isin(student[(student['fname'] == 'Linda') & (student['lname'] == 'Smith')]['stuid'])]['clubid'].count()