Practice / aggregations
Waveform's merch store wants to see what each shopper is holding.
You have the cart DataFrame:
Your task: return each user_id and a column items — the distinct products in that user's cart, as an alphabetically sorted list.
Assign your answer DataFrame to result. Row order doesn't matter.
cartinput DataFrame| column | type |
|---|---|
| user_id | long |
| item | string |
| user_id | item |
|---|---|
| 1 | Pen |
| 1 | Pen |
| 1 | Notebook |
| 2 | Eraser |
user_iditems· 2 rowsF.collect_set("item") gathers the distinct items per group. Wrap it in
F.sort_array(...) so the list comes back in a stable alphabetical order.
This problem builds on Aggregations & groupBy (~7 min). Pop it open in a new tab if you want a quick recap.