What you are doing in your code is retrieving the y-value of each hand and writing them on the same variable (playerpos), overwriting the previous value in the process.

You can read the for loop as follows: " for each Hand named hand in leap.getHandList(), do the following: " (this is a variation on the for loop, recognisable by the colon).
If you look closely to the example, you see that in each iteration, an ellipse is drawn at the x and y position of the hand. But in your code, it writes the y value of each hand to the same variable, so you end up with the y value of the last hand. What you want to do is use a structure like a FloatList (which is equivalent to an ArrayList but with float variables as its elements).

When initializing your variables, include this:

1. FloatList playerPos;
2. void setup(){
3.    playerPos = new FloatList();
4. }
   

Then use this structure:

1. for (Hand hand : leap.getHandList()) {
   
     PVector handPos = leap.getPosition(hand);
     playerPos.append(handPos.y);
   }
   
   

You can retrieve the position with this method:

1. yPosOfFirstHand = playerPos.get(0);

It's been a while since this question got asked so I hope it's helpful anyway!