php中怎么去除二维数组的某个字段？

$arr = array(  "net" => array("on", "11", "101", "1001"),  "login" => array("on", "10001","100001","1000001"));array_walk($arr, function(&$t) {  $t = array_diff($t, array('on'));});print_r($arr);

Array(    [net] => Array        (            [1] => 11            [2] => 101            [3] => 1001        )    [login] => Array        (            [1] => 10001            [2] => 100001            [3] => 1000001        ))

$arr = array(  "net" => array("on", "11", "101", "1001"),  "login" => array("on", "10001","100001","1000001"));$str ='';foreach ($arr as $key=>$value){    foreach ($value as $k =>$v){        if($v != 'on') $str = $str|$v;    }}var_dump($str);

string(7) "1111111"

$arr = array("net" => array("on", "11", "101", "1001"),    "login" => array("on", "10001","100001","1000001"));delon($arr);print_r($arr);function delon(&$arr){	foreach($arr as $key=>&$val){		foreach($val as $k=>$v){			if($v=='on'){				unset($val[$k]);			}		}	}}

$arr = array("net" => array("on","1", "2","4"), "login" => array("on","10001","100001","10000001"));delon($arr);$str ='';foreach ($arr as $key=>$value){    foreach ($value as $k =>$v){        $str=$str|$v;    }}var_dump($str); function delon(&$arr){    foreach($arr as $key=>&$val){        foreach($val as $k=>$v){            if($v=='on'){                unset($val[$k]);            }        }    }}