A vertical format algorithm for mining frequent item sets

Apriori is a classical algorithm for association rules. In order to get the support degree of candidate sets, Apriori needs to scan the database for many times. This paper presents a new algorithm, which mine frequent item sets with vertical format. The new algorithm only needs to scan database one time. And in the follow-up data mining process, it can get new frequent item sets through `and operation´ between item sets. The new algorithm needs less storage space, and can improve the efficiency of data mining.