Mark Giuliano เข้าร่วมกิจกรรมกี่กิจกรรม?
How many activities does Mark Giuliano participate in?
df1 = pd.DataFrame(columns=['facID']); df2 = pd.DataFrame(columns=['facID', 'fname', 'lname'])
df1[df1['facID'].isin(df2[(df2['fname'] == 'Mark') & (df2['lname'] == 'Giuliano')]['facID'])].shape[0]