Скачать или смотреть Apriori Algorithm - Finding frequent item sets

Apriori is a seminal algorithm proposed by R.Agarwal & R.Srikant in 1994 for mining frequent itemsets for Boolean association rules. The name of the algorithm is based on the fact that the algorithm uses 'prior' knowledge of frequent itemset properties. Apriori employs an iterative approach known as level - wise search, where k-itemsets are used to explore (k+1) itemsets.
First the set of frequent 1 itemset is found by scanning the Database to accumulate the count of each item, and collecting those items that satisfy minimum support. The resulting set is denoted by L1, next L1 is used to find L2, the set of frequent 2-item sets, which is used to find L3 and so on.. untill no more frequent k-itemsets can be found.