public List<GameObject> itemsInInv = new List<GameObject>();

var len = currentPosition;
    items.transform.localPosition = new Vector3(44 * (len % 4), -36 * (len / 4), 0f);

itemsInInv.Remove(obj.gameObject);
    Destroy(obj);

for(var i =0; i < itemsInInv.Count; i++)
    {
        itemsInInv[i].transform.localPosition = new Vector3(44 * (i % 4), -36 * (i / 4), 0f);
    }