Count Value Exclude Duplicated ID

I have dataframe

df1 = pd.DataFrame({'id': ['1','2','2','3','3','4','5'],
                    'event': ['Basket','Soccer','Soccer','Basket','Soccer','Basket','Soccer']})

I want to count unique values of event but exclude the repeated id. The result I expect are:

event   count   
Basket  3       
Soccer  3       

>Solution :

This will work:

df1.groupby('event').agg({'id':lambda x: len(pd.unique(x))})

# OR

df1.groupby(['event']).agg(['nunique'])

Output: