What is the Apriori algorithm in association rule mining?

Updated May 15, 2026

Short answer

Apriori finds frequent itemsets using a bottom-up approach.

Deep explanation

Apriori uses the property that all subsets of a frequent itemset must also be frequent. It iteratively generates candidate itemsets and prunes those below a support threshold. This reduces computational complexity in market basket analysis.

Real-world example

Supermarkets identifying that bread and butter are often bought together.

Common mistakes

  • Ignoring support threshold leading to explosion of candidate sets.

Follow-up questions

  • What is support pruning?
  • What is FP-Growth?

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