Miscellany

 for ($i=0;$i<24*60;$i+=$intervalAmount) {
       for ($p=1;$p<=$counter;$p++) {
               if ($arr[$i]==$this->calendar_items[$p]["id"]) {
                       $arr[$i]=$p;
       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;
                }
        }
 }