变量未分配

Question

This has been driving me crazy. When I put:

for($i = 0; $i < sizeOf($clones); $i++) {
        $clones[$i]->attackGroup = $_POST['type'][$i];
}

$clones[2]->attackGroup does not get assigned. But when I put:

for($i = 0; $i < sizeOf($clones); $i++) {
    if($i == 2) {    
        $clones[$i]->attackGroup = $_POST['type'][$i];
    }

}

It does.... How is this possible?