Regroup array to tree structure in PHP -

i have array one:

$array = array(     array('id' => 'foo.bar'),     array('id' => 'foo'),     array('id' => 'foo.baz.bar'),     array('id' => 'foo.bar.bar'), ); 

i can split id fields them paths, , i'd sort them tree... tried this:

$result = array();  foreach($array $element) {     $path = explode('.', $element['id']);      $subtree = $result;     while(!empty($path)) {         $path_element = array_shift($path);          if(empty($path_element)) {             $subtree['data'] = $element;         } else {             if(!is_array($subtree[$path_element])) {                 $subtree[$path_element] = array();             }             $subtree = $subtree[$path_element];         }     } } 

but load of warnings , empty $res-array.

php notice:  undefined index: foo in tree.php on line 24 php stack trace: php   1. {main}() tree.php:0 php notice:  undefined index: bar in tree.php on line 24 php stack trace: php   1. {main}() tree.php:0 php notice:  undefined index: foo in tree.php on line 24 php stack trace: php   1. {main}() tree.php:0 php notice:  undefined index: foo in tree.php on line 24 php stack trace: php   1. {main}() tree.php:0 php notice:  undefined index: baz in tree.php on line 24 php stack trace: php   1. {main}() tree.php:0 php notice:  undefined index: bar in tree.php on line 24 php stack trace: php   1. {main}() tree.php:0 php notice:  undefined index: foo in tree.php on line 24 php stack trace: php   1. {main}() tree.php:0 php notice:  undefined index: bar in tree.php on line 24 php stack trace: php   1. {main}() tree.php:0 php notice:  undefined index: bar in tree.php on line 24 php stack trace: php   1. {main}() tree.php:0 

(line 24 $s = $s[$pe];)

any hint?

edit: desired output this

$res = array(   'foo' => array(     'data' => ...     'bar' => array(       'data' => ...       'bar' => array(         'data' => ...       ),     ),     'baz' => array(       'bar' => array(         'data' => ...       ),     ),   ), ); 

the data elements original elements array.

the code below generates following result:

array (     [foo] => array     (         [data] => ...         [baz] => array             (                 [bar] => array                     (                         [data] => ...                     )          )          [bar] => array         (             [bar] => array             (                 [data] => ...             )         )     ) ) 

i renamed of you're variables...

$array = array(     array('id' => 'foo.bar'),     array('id' => 'foo'),     array('id' => 'foo.baz.bar'),     array('id' => 'foo.bar.bar'), );   $res = array();  foreach($array $e) {      $parts = explode('.', $e['id']);      $temp = &$res;      foreach($parts $key => $el) {         if (!isset($temp[$el])) $temp[$el] = array();          if ($key == count($parts)-1) $temp[$el] = array('data' =>  '...');         $temp = &$temp[$el];     } }  print_r($res);