apriori算法java代码

以下是apriori算法的Java代码示例：

public static ArrayList<ArrayList<String>> apriori(ArrayList<ArrayList<String>> transactions, int minSup) {
    ArrayList<ArrayList<String>> itemsets = new ArrayList<ArrayList<String>>();
    ArrayList<ArrayList<String>> L = new ArrayList<ArrayList<String>>();
    ArrayList<ArrayList<String>> C = new ArrayList<ArrayList<String>>();
    int k = 0;
    int transactionsSize = transactions.size();
    while (k == 0 || !L.isEmpty()) {
        if (k == 0) {
            for (ArrayList<String> transaction : transactions) {
                for (String item : transaction) {
                    ArrayList<String> itemset = new ArrayList<String>();
                    itemset.add(item);
                    if (!C.contains(itemset)) {
                        C.add(itemset);
                    }
                }
            }
        } else {
            C = generateC(L);
        }
        for (ArrayList<String> transaction : transactions) {
            for (ArrayList<String> c : C) {
                if (transaction.containsAll(c)) {
                    incrementCount(itemsets, c);
                }
            }
        }
        L.clear();
        for (ArrayList<String> itemset : itemsets) {
            int count = getCount(itemsets, itemset);
            if (count >= minSup && !L.contains(itemset)) {
                L.add(itemset);
            }
        }
        k++;
    }

    return itemsets;
}

private static ArrayList<ArrayList<String>> generateC(ArrayList<ArrayList<String>> L) {
    ArrayList<ArrayList<String>> C = new ArrayList<ArrayList<String>>();
    for (int i = 0; i < L.size(); i++) {
        for (int j = i + 1; j < L.size(); j++) {
            ArrayList<String> c = new ArrayList<String>();
            for (String item : L.get(i)) {
                if (!c.contains(item)) {
                    c.add(item);
                }
            }
            for (String item : L.get(j)) {
                if (!c.contains(item)) {
                    c.add(item);
                }
            }
            Collections.sort(c);
            if (!C.contains(c)) {
                C.add(c);
            }
        }
    }
    return C;
}

private static void incrementCount(ArrayList<ArrayList<String>> itemsets, ArrayList<String> itemset) {
    for (int i = 0; i < itemsets.size(); i++) {
        if (itemsets.get(i).equals(itemset)) {
            int count = Integer.parseInt(itemsets.get(i).get(itemsets.get(i).size() - 1));
            itemsets.get(i).set(itemsets.get(i).size() - 1, Integer.toString(count + 1));
            return;
        }
    }
    itemset.add("1");
    itemsets.add(itemset);
}

private static int getCount(ArrayList<ArrayList<String>> itemsets, ArrayList<String> itemset) {
    for (ArrayList<String> i : itemsets) {
        if (i.equals(itemset)) {
            return Integer.parseInt(i.get(i.size() - 1));
        }
    }
    return 0;
}