How to get the required combination of two numbers from an arraylist?

Question

I have an ArrayList of some elements path = [1, 2, 5, 7]. Now I want to get values from these elements like:

1,2 
2,5
5,7 

I used list iterator for this purpose, but what I am getting is:

1,2 
2,2     
5,7 
7,7

I have seen this answer: how to get all combination of an arraylist? But I don't need all the combinations like this.

My code is:

public class iterator {

public static void main(String[] args){
    ArrayList<String> path=new ArrayList<>();
    path.add("1");
    path.add("2");
    path.add("5");
    path.add("7");

    System.out.println(path);
    ListIterator<String> itr =  path.listIterator();  
    while(itr.hasNext())
    {
        System.out.println(itr.next()+ "," + itr.next());
        System.out.println(itr.previous()+ "," + itr.next());
    }

}

}

My question is how can I get my required result?

Answer 1

for (int i = 0; i < path.size() - 1; i++) {
    System.out.println(path.get(i) + "," + path.get(i + 1));
}

Answer 2

You can try traditional for loop with counter to achieve this:

for (int i = 0; i < path.size() - 1; i++) {
    System.out.println(path.get(i) + ", " + path.get(i+1));
}

Answer 3

The issue is that .next() gets the next element and advances the cursor. To use your ListIterator, you would do it like this:

while (itr.nextIndex() + 1 < path.size()) {
    System.out.println(itr.next() + "," + itr.next());
    itr.previous(); // back up 1 to get the duplicate
}