//recreate the array.
for ($i=0;$i<24*60;$i+=$intervalAmount) {
        echo "=with i on $i we have arr[i] on ".$arr[$i]."\n";
        for ($j=1;$j<=$counter;$j++) {
                echo "==with i on $i and j on $j we have arr[i] on ".$arr[$i]."\n";
                if ($arr[$i]==$this->calendar_items[$j]["id"]) {
                        $arr[$i]=$j;
                        break;
                }
        }
}