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

You could pass the length to the function and increment it when you call recursively and then use the variable $length to determine the depth

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

    $html = '
' . PHP_EOL;

    foreach ( $arr as $v ) {

        $html.= '
' . $v['name'] . '
' . PHP_EOL;

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

    }

    $html.= '
' . PHP_EOL;

    return $html;
}

This is what i do usually to keep track of recursion depth and it usually get the job done