How to recursively build a <select> with unknown tree depth

Question

I have a MySQL table with a tree data structure. The fields are _id, name and parentId. When the record hasn\'t a parent, parent

Answer 1

Pass a parameter to count the iteration like $pass

function toUL ($arr, $pass = 0) {

    $html = '
' . PHP_EOL;

    foreach ( $arr as $v ) {           

        $html.= '
';
        $html .= str_repeat("--", $pass); // use the $pass value to create the --
        $html .= $v['name'] . '
' . PHP_EOL;

        if ( array_key_exists('children', $v) ) {
            $html.= toUL($v['children'], $pass+1);
        }

    }

    $html.= '
' . PHP_EOL;

    return $html;
}