Count the number of items in my array list

Question

I want to count the number of itemids in my array, can i get an example of how i would go about adding this to my code. code below;

if (value != null && !value.isEmpty()) {     Set set = value.keySet();     Object[] key = set.toArray();     Arrays.sort(key);      for (int i = 0; i < key.length; i++) {         ArrayList list = (ArrayList) value.get((String) key[i]);          if (list != null && !list.isEmpty()) {             Iterator iter = list.iterator();             double itemValue = 0;             String itemId = "";              while (iter.hasNext()) {                 Propertyunbuf p = (Propertyunbuf) iter.next();                 if (p != null) {                     itemValue = itemValue + p.getItemValue().doubleValue();                     itemId = p.getItemId();                 }                  buf2.append(NL);                 buf2.append("                  " + itemId);              }              double amount = itemValue;             totalAmount += amount;         }     } } 

Answer 1

The number of itemIds in your list will be the same as the number of elements in your list:

int itemCount = list.size(); 

However, if you're looking to count the number of unique itemIds (per @pst) then you should use a set to keep track of them.

Set<String> itemIds = new HashSet<String>();  //... itemId = p.getItemId(); itemIds.add(itemId);  //... later ... int uniqueItemIdCount = itemIds.size();