pandas groupby count the number of zeros in a column

Question

I have a dataframe, e.g:

Date             B           C   
20.07.2018      10           8
20.07.2018       1           0
21.07.2018       0           1
21.07.201         


        

Answer 1

I believe need DataFrameGroupBy.agg with compare by 0 and sum:

df1 = df.groupby('Date').agg(lambda x: x.eq(0).sum())
print (df1)

            B  C
Date            
20.07.2018  0  1
21.07.2018  1  1

---

df2 = df.groupby('Date').agg(lambda x: x.ne(0).sum())
print (df2)
            B  C
Date            
20.07.2018  2  1
21.07.2018  1  1