我的php变量有问题[关闭]

Question

I keep getting "Undefined Index" for the following:

$username = $_POST['username'];
$email = $_POST['email'];
$email1 = "@";
$email_check = strpos($email,$email1);
$pwd = $_POST['pwd'];
$pwd_conf = $_POST['pwd_conf'];
$uLength = strlen($username);
$pLength = strlen($pwd);

I have already tried if(isset()) but the error only changed to "Undefined Variable"

if (isset($_POST['username'])) {
    $username = $_POST['username'];
}
if (isset($_POST['email'])) {
    $email = $_POST['email'];
}
$email1 = "@";
$email_check = strpos($email, $email1);
if (isset($_POST['pwd'])) {
    $pwd = $_POST['pwd'];
}
if (isset($_POST['pwd_conf'])) {
    $pwd_conf = $_POST['pwd_conf'];
}
$uLength = strlen($username);
$pLength = strlen($pwd);

Answer 1

use this

if(isset($_POST['username'])) {
    $username = $_POST['username'];
    $uLength = strlen($username);
}
if(isset($_POST['email'])) {
    $email = $_POST['email'];
    $email1 = "@";
    $email_check = strpos($email,$email1);
}

if(isset($_POST['pwd'])) {
    $pwd = $_POST['pwd'];
    $pLength = strlen($pwd);
}
if(isset($_POST['pwd_conf'])) {
    $pwd_conf = $_POST['pwd_conf'];
}