问个二位数组操作有关问题

$aa = array(<br />  array("id"=>"1","time"=>"5","neirong"=>"www"),<br />  array("id"=>"2","time"=>"55","neirong"=>"www"),<br />  array("id"=>"4","time"=>"555","neirong"=>"www"),<br />  array("id"=>"5","time"=>"555","neirong"=>"www"),<br />);<br /><br />$bb = array(<br />  array("id"=>"1","time"=>"5"),<br />  array("id"=>"2","time"=>"50"),<br />  array("id"=>"3","time"=>"555"),<br />);<br /><br />foreach($aa as $v) $r[$v['id']] = $v;<br />foreach($bb as $v) {<br />  $k = $v['id'];<br />  if(! isset($r[$k])) $r[$k] = $v;<br />  elseif($r[$k]['time'] < $v['time']) $r[$k] = $v;<br />  elseif($r[$k]['time'] == $v['time']) unset($r[$k]);<br />}<br />ksort($r);<br />print_r($r);

Array<br />(<br />    [2] => Array<br />        (<br />            [id] => 2<br />            [time] => 55<br />            [neirong] => www<br />        )<br /><br />    [3] => Array<br />        (<br />            [id] => 3<br />            [time] => 555<br />        )<br /><br />    [4] => Array<br />        (<br />            [id] => 4<br />            [time] => 555<br />            [neirong] => www<br />        )<br /><br />    [5] => Array<br />        (<br />            [id] => 5<br />            [time] => 555<br />            [neirong] => www<br />        )<br /><br />)<br /><br />