Ask for a simple recursive

$arr = Array (
Array
' id ' = 1,
' ParentID ' = 0,
' Title ' = ' A '
),
Array
' id ' = 2,
' ParentID ' = 1,
' title ' = ' A-1 '
),
Array
' id ' = 3,
' ParentID ' = 1,
' title ' = ' A-1 '
),
Array
' id ' = 4,
' ParentID ' = 2,
' Title ' = ' A-1-1 '
)
);

The recursive conversions are as follows:
$arr = Array (
Array
' id ' = 1,
' ParentID ' = 0,
' Title ' = ' A ',
' Child ' = = Array (
Array
' id ' = 2,
' ParentID ' = 1,
' title ' = ' A-1 ',
' Child ' = = Array (
......
)
Array
' id ' = 3,
' ParentID ' = 2,
' Title ' = ' A-2 '
)
),
......
);
How would you like to write this recursion?

Reply to discussion (solution)

function Findchildren ($list, $p =0) {  $r = array ();  foreach ($list as $id + $item) {    if ($item [' parentid '] = = $p) {      $r [$id] = $item;      if ($t = Findchildren ($list, $item [' id '])        $r [$id] [' children '] [] = $t;    }  }  return $r;}        $arr = Array (        ' id ' = = 1,        ' parentid ' = + 0,        ' title ' = ' A '    ),    Array (        ' id ' = 2,        ' parentid ' = 1,        ' title ' = ' A-1 '    ),    array (        ' id ' = 3,        ' ParentID ' = 1,        ' title ' = ' A-1 '    ),    array (        ' id ' = = 4,        ' ParentID ' + 2,        ' title ' = ' = ') A-1-1 '    )  );p Rint_r (Findchildren ($arr));

Array
(
[0] = = Array
(
[id] = 1
[ParentID] = 0
[Title] = a
[children] = = Array
(
[0] = = Array
(
[1] = = Array
(
[id] = 2
[ParentID] = 1
[Title] = A-1
[children] = = Array
(
[0] = = Array
(
[3] = = Array
(
[id] = 4
[ParentID] = 2
[Title] = A-1-1
)

)

)

)

[2] = = Array
(
[id] = 3
[ParentID] = 1
[Title] = A-1
)

)

)

)

)

