Top N per-group [Obj,String]

Description

Select for each group the top-N results. This blocks requires a list of pairs [OBJ,STRING] as the input. The groups are created on the first column, thus the second column is grouped by the first. The results are also returned as a list of pairs. Thus each member of the group as a separate result.

Input

• SOURCE [OBJ,STRING]: the list of pairs to filter. Distinct values in the first column identify groups

Output

• RESULT [OBJ,STRING]: the top-N objects for each group

Parameters

• N: the number of results to return