1，PDO连接数据库常语句
$dsn = "mysql:host=xxx.xxx.xxx.xxx:port;dbname=xxx;charset=utf8";
$pdo = new PDO($dsn,$username,$pass) or die("connect failed");
注:charset只能用utf8（大小写都行）形式，不能写成utf-8
2，遍历数组
$array = array("1","2","3");
foreach($array as $key => $value){
echo $key." ".$value;
}