//implode 使用一个字符串将数组变成字符串
$array = array('lastname', 'email', 'phone');
$comma_separated = implode(",", $array);
echo $comma_separated; // lastname,email,phone
//explode — 使用一个字符串分割另一个字符串，返回一个数组
// 示例 1
$pizza = "piece1 piece2 piece3 piece4 piece5 piece6";
$pieces = explode(" ", $pizza);
echo $pieces[0]; // piece1
echo $pieces[1]; // piece2
// 示例 2
$data = "foo:*:1023:1000::/home/foo:/bin/sh";
list($user, $pass, $uid, $gid, $gecos, $home, $shell) = explode(":", $data);
echo $user; // foo
echo $pass; // *