php数组转xml，纯数据

   public static function arrToXml($data)
    {
        $xml=$attr="";
        foreach ($data as $key => $value) {
            if (is_numeric($key)) {
                $xml.=is_array($value)?self::arrToXml($value):$value; 
            }else{
                $xml .= "<{$key}>";
                $xml.=is_array($value)?self::arrToXml($value):$value;
                $xml.="\n";                
            }
        }
        return $xml;
    }