Ready to begin
No records have been processed. Start with Next step.
SECTION 21 / 24
One bill item becomes one customer–shop–category triple
REAL COURSE DATA · BUILD AND UNPACK LISTS
Turn Bill 1 item rows into triples
Follow one occurrence at a time. Choose another input to test empty lists, repeated IDs and different parameters.
Ready
What we remember
- Processed
- 0
Predict the next change, then step through the list. The original course records remain unchanged.
A bill contains several item rows. For each row, keep [Customer,Store,Category]. This produces one triple per ITEM ROW, not one per bill and not one per individual unit purchased. The customer and store repeat across a bill’s rows.
| Bill 1 item | Category | Triple |
|---|---|---|
| Carrots | Vegetables/Food | [Srivatsan, SV Stores, Vegetables/Food] |
| Soap | Toiletries | [Srivatsan, SV Stores, Toiletries] |
| Tomatoes | Vegetables/Food | [Srivatsan, SV Stores, Vegetables/Food] |
| Bananas | Vegetables/Food | [Srivatsan, SV Stores, Vegetables/Food] |
| Socks | Footwear/Apparel | [Srivatsan, SV Stores, Footwear/Apparel] |
| Curd | Dairy/Food | [Srivatsan, SV Stores, Dairy/Food] |
| Milk | Dairy/Food | [Srivatsan, SV Stores, Dairy/Food] |
Bill 1 therefore gives 7 triples, including 5 food item rows. Repeated Vegetables/Food triples are not accidental duplicates: they came from different rows. Deduplicating them changes the question to distinct customer–shop–category combinations and loses item-row frequencies.
From all item triples you could count rows for a shop, customer or category, or combine filters. But quantity, price and cost are omitted. These triples alone cannot tell total units, kilograms, revenue or how many bills were issued. Our complete item-row trace uses the verified Bill 1 rows; the 30-bill summary’s MajorCategories is not an item-by-item list and must not be expanded into invented rows.
Try it yourself
Does counting triples for Bananas measure the quantity 8 in Bill 1?
Show explained answer
No. The Bananas row contributes one triple. Quantity 8 was not retained in this projection.
Try it yourself
Why do Carrots and Tomatoes create equal category triples?
Show explained answer
They share customer, shop and category but are different item rows. The list retains both occurrences.
Try it yourself
Can [Customer,Store,Category] alone compute bill revenue?
Show explained answer
No. The representation omitted price and cost. Keep those fields or return to the original records for revenue questions.