Question

I’ve done some searching but I wasn’t able to find a valid solution. I have an arraylist storing Strings such as gum, socks, OJ, dog food…

I am having trouble iterating the list to determine the total number of differnt types of items.

ie.

ArrayList<String> Store = new ArrayList<String>();
    this.Store.add("Gum");
    this.Store.add("Gum");
    this.Store.add("Socks");
    this.Store.add("Candy");

The list has 4 total items, but only three different kinds of items (Gum, Sucks, Candy).

How would I design a method to calculate the 3?

Answer 1

What Bhesh Gurung said, but in code:

int numUnique = new HashSet<String>(Store).size();

If what you actually have is StoreItems and need to go through getName() then I would do

Set<String> itemNames = new HashSet<String>();
for (StoreItem item : Store)
    itemNames.add(item.getName());
int numUnique = itemNames.size();