group by pandas dataframe and select latest in each group

You can also use tail with groupby to get the last n values of the group:

df.sort_values('date').groupby('id').tail(1)

    id  product date
2   220 6647    2014-10-16
8   901 4555    2014-11-01
5   826 3380    2015-05-19

use idxmax in groupby and slice df with loc

df.loc[df.groupby('id').date.idxmax()]

    id  product       date
2  220     6647 2014-10-16
5  826     3380 2015-05-19
8  901     4555 2014-11-01