php - Build a nested array from a menu in database -

i have following output database , want build menu data.

$output = [     ['id_struct' => 1, 'title' => 'a', 'parent' => 0],     ['id_struct' => 2, 'title' => 'b', 'parent' => 0],     ['id_struct' => 3, 'title' => 'b1', 'parent' => 2],     ['id_struct' => 4, 'title' => 'b2', 'parent' => 3],     ['id_struct' => 5, 'title' => 'c', 'parent' => 0], ]; 

with output need build array this:

array (size=3)   0 =>      array (size=1)       'title' => string 'a' (length=1)   1 =>      array (size=2)       'title' => string 'b' (length=1)       'children' =>          array (size=1)           0 =>              array (size=2)               'title' => string 'b1' (length=2)               'children' =>                  array (size=1)                   0 =>                      array (size=1)                       'title' => string 'bb1' (length=3)   2 =>      array (size=1)       'title' => string 'c' (length=1) 

it needs format can export json.

what best way achieve this? i've found many solutions of them export menu html using print/echo , not work here.

try this:

function buildtree(array $elements, $parentid = 0) {  $branch = array();  foreach ($elements $element) {     if ($element['parent'] == $parentid) {         $children = buildtree($elements, $element['id_struct']);         if ($children) {             $element['children'] = $children;         }         $branch[] = $element;     } }   return $branch; }  $tree = buildtree($output); echo "<pre>"; print_r( $tree ); echo "</pre>"; 

hope helps.