Pandas Groupby How to Show Zero Counts in DataFrame

Question

I have the following Pandas dataframe:

Name   | EventSignupNo | Attended | Points
Smith  | 0145          | Y        | 20.24
Smith  | 0174          | Y                


        

Answer 1

You could do this with groupby + agg. For your exact output with Y and N at each level, you'd need reindex:

g = df.groupby(['Name', 'Attended'], sort=False).Points.agg(['count', 'sum'])

g
                 count    sum
Name   Attended              
Smith  Y             2  49.38
       N             1   0.00
Adams  N             1   0.00
       Y             1  33.43
Morgan Y             2  54.38

idx = pd.MultiIndex.from_product([g.index.levels[0], ['Y', 'N']])

idx
MultiIndex(levels=[['Adams', 'Morgan', 'Smith'], ['N', 'Y']],
           labels=[[2, 2, 0, 0, 1, 1], [1, 0, 1, 0, 1, 0]])


g.reindex(idx, fill_value=0)

          count    sum
Smith  Y      2  49.38
       N      1   0.00
Adams  Y      1  33.43
       N      1   0.00
Morgan Y      2  54.38
       N      0   0.00