Why does SortedSet class has no .get(location) method?

[Aditya Sirohi]

Hi,

I have put some data in the SortedSet, but i can only iterate over it using an iterator. If i have to get a element on a certain index i need to first put elements from the SortedSet to ArrayList and then do a .get(location). Is there any other better less expensive way to get a element on a certain index in SortedSet?

-Adi

[fred rosenberger]

The subset method wouldn't work?

[Mike Simmons]

Fundamentally, a Set doesn't have an index for each position. If that's what you want, you should probably use a List instead.

[Mike Simmons]

I don't see how a subset method would work - how would you use an index in that?

[Rob Spoor]

Aditya Sirohi wrote:I have put some data in the SortedSet, but i can only iterate over it using an iterator. If i have to get a element on a certain index i need to first put elements from the SortedSet to ArrayList and then do a .get(location). Is there any other better less expensive way to get a element on a certain index in SortedSet?

Iterate until you've reached the index:

public static <E> E get(Collection<E> collection, int index)
{
    Iterator<E> i = collection.iterator();
    E element = null;
    while (i.hasNext() && index > 0)
    {
        element = i.next()
    }
    return element;
}

This code is flawed as it doesn't check if index is valid, but you can use this basic principle.

This is slightly better than using an ArrayList, because with that you have to iterate over all the elements, even those past the index you want. After all, adding the SortedSet elements into the ArrayList requires all of the elements to be iterated over.

[Mike Simmons]

Rob Spoor wrote:

    while (i.hasNext() && index > 0)

I think this needs to be something like:

    while (i.hasNext() && index-- >= 0)

[fred rosenberger]

Mike Simmons wrote:I don't see how a subset method would work - how would you use an index in that?

I didn't read it closely enough. I thought you could say "from element 2 to element 3"

[Rob Spoor]

Mike Simmons wrote:

Rob Spoor wrote:

    while (i.hasNext() && index > 0)

I think this needs to be something like:

    while (i.hasNext() && index-- >= 0)

Yes, of course... I forgot to decrement index, and index can of course be 0 as well