How to Count Repetition of Words in Array List?

Question

I\'ve these code for searching occurrence in Array-List but my problem is how I can get result out side of this for loop in integer type cause I need in out side , may be th

Answer 1

I would sort the list first to avoid going thru the whole list with Collections.frequency every time. The code will be longer but much more efficient

    List list = new ArrayList();
    list.add("aaa");
    list.add("bbb");
    list.add("aaa");
    Map map = new HashMap();
    Collections.sort(list);
    String last = null;
    int n = 0;
    for (String w : list) {
        if (w.equals(last)) {
            n++;
        } else {
            if (last != null) {
                map.put(last, n);
            }
            last = w;
            n = 1;
        }
    }
    map.put(last, n);
    System.out.println(map);

output

{aaa=2, bbb=1}