Trying to get the size of an inner arraylists of class object inside an outer arraylist of arraylists

Question

i have an array list of arraylists of object type trying to get the size of a specific array list but i keep getting the size of the the whole arraylist

healthyKoalas = new ArrayList<Koala>();
hKoalas = new ArrayList<ArrayList<Koala>>();

public void hkoala(int x)
    {
         for (int i=0; i<x; i++) // x is the number of healthy koalas in an observation point
         {
             int age = (int)(Math.random()*18)+1; 
             Koala k = new Koala(age); 
             addHKoala(k);
             healthyKoalas.sort(Comparator.comparing(Koala::getAge).reversed());
             //Collections.sort(healthyKoalas, Collections.reverseOrder());
            }
        hKoalas.add(healthyKoalas);
    }

then when i try

hKoalas.get(x).size();

it gives me the number of all the koala objects while i want to get the size of a specific inner arraylist

Does [this](https://stackoverflow.com/a/8684644/11754886) answer your question? — fjsv, Jun 09 '20 at 23:15
Please provide more info, for example the arraylist(s), so we can understand your point better. — Kaimson, Jun 09 '20 at 23:19
then when try to use hKoalas.get(x).size() i get the number of every k object in the arraylist not the numer at position x — abdelmohsen edris, Jun 09 '20 at 23:48

score 1 · Answer 1 · answered Jun 09 '20 at 23:57

Given hKoalas = new ArrayList<ArrayList<Koala>>();, then hKoalas.get(1).size() will give you the number of elements of the second 'inner list' (index 1 = the second one in the store, as index 0 is the first one). If you think it is returning the count of ALL koalas across all the inner lists, you've got another bug in your code and you have misidentified what's happening.

Trying to get the size of an inner arraylists of class object inside an outer arraylist of arraylists

1 Answers1