モデレーターのxuzuningさんに聞いてください

<br />
$ar = array (<br />
  array("level" => '1', "caption" => "一级菜单1"),<br />
  array("level" => '1', "caption" => "一级菜单2"),<br />
  array("level" => '2', "caption" => "二级菜单1"),<br />
  array("level" => '2', "caption" => "二级菜单2"),<br />
  array("level" => '3', "caption" => "三级菜单1"),<br />
  array("level" => '1', "caption" => "一级菜单3"),<br />
);<br />
print_r( foo($ar));<br />
<br />
function foo(&$ar, $level='1') {<br />
  $res = array();<br />
  while($r = current($ar)) {<br />
    if($r['level'] > $level) $res[count($res)-1]['sub'] = foo($ar, $r['level']);<br />
    elseif($r['level'] == $level) $res[] = $r;<br />
    else {<br />
      array_unshift($ar, $r);<br />
      break;<br />
    }<br />
    array_shift($ar);<br />
  }<br />
  return $res;<br />
}<br />