Syllabus Lesson 132 of 141 · Ten doors and the field kit
Ten doors and the field kit

Final 1: one row per supplier

AI off This is a final exam, matched to the baseline exam you did in the first module: the same kind of problem, new data, the same difficulty. The tutor is switched off and there are no hints. Work alone. The course lines it up against your baseline in the next lesson.

Finance has three years of supplier records from two old systems and wants one row per supplier before the next payment run. The same firm appears with "Ltd" and "Limited", with tax numbers typed with spaces and dots, and in different cities when a branch registered separately.

The worked example

1  Granite Tools Ltd        GB 123 456.789   Leeds
2  GRANITE TOOLS LIMITED    (none)           leeds
3  Granite Tools Ltd.       gb-123456789     Cork
4  Granite Tools plc        IE1234567X       Cork
5  granite tools            ie 1234567x      Dublin
6  Oak Paper                (none)           Lyon
7  Swift Glass              (none)           Porto
8  Oak Paper plc            FR 99 887        Brno
# -> [[1, 2, 3, 4, 5], [6], [7], [8]]
Your turn

Write merge_suppliers(records). Each record is a dict with "id" (a unique whole number), "company", "vat" (a tax number) and "city". Return a list of groups, one per real supplier; each group is a list of ids, and every id appears in exactly one group. Order does not matter.

  • VAT rule: two records are the same supplier if their VAT numbers match after you remove spaces, dots and dashes and uppercase (gb-123 456.789 is GB123456789). An empty VAT number matches nothing.
  • Name rule: they are also the same supplier if their company names match after you remove dots and commas, lowercase, split into words and drop a last word that is ltd, limited or plc, and their cities match after trimming and lowercasing.
  • Chains: if A matches B and B matches C, all three are one supplier, even if A and C share nothing.
Budget: on 1,400 records your code may run at most 200,000 steps (steps(), lines of your own code).

AI off: no tutor, hints or worked solution on this one. Your own thinking only.

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