How to make dynamic drop down in php? - codeigniter

Question

I want to make a dynamic drop down in CI.I had done it in CI by directly passing the values from model With its design by concatenation the html.. But now i want it without the html i.e. the function just only should return the array ...
my before function was something like this...
function category() {
$sql = $this->db->query("select * from ss_category where parent_id='0'");
$result = $sql->result();
//print_r($result);die();
$output = array();
foreach ($result as $ra) {
$output=$this->get_child($ra->cat_id);
}
//print_r($output);die();
return $output;
}
function get_child($parent_id) {
//echo "select * from ss_category where parent_id=" . $parent_id;
$sql = $this->db->query("select * from ss_category where parent_id=" . $parent_id);
$r = $sql->result();
if (!empty($r)) {
foreach ($r as $s) {
$this->get_child($s->cat_id);
}
//print_r($child);
}
//print_r($r);
}
I want to make drop down something like this..
-parent 1
-child 1
-subchild 1
-child 2
-child 3
-subchild 1
-parent 2
-child 1
My table structure is like this..
+---------------------------------------------------------------+
| cat_id category_name cat_slug parent_id level description |
+---------------------------------------------------------------+
| 1 Elecotronics Electronics 1 description |
+---------------------------------------------------------------+

Answer 1

function parent_sort($categories)
{
foreach($categories as $item)
$childs[$item->parent_id][] = $item;
foreach($categories as $item)
if (isset($childs[$item->category_id]))
$item->childs = $childs[$item->category_id];
return $childs[0];
}