# Top N per-group

### Description
Select for each group the top-N results.
This blocks requires a list of pairs `[OBJ,OBJ]` 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,OBJ]`: the list of objects pairs to filter. Distinct values in the first column identify groups

### Output
- `RESULT [OBJ,OBJ]`: the top-N objects for each group

### Parameters
- `N`: the number of results to return