Using '&&' inside foreach?

I am looking for smart solution, maybe you could help me out. Currently I am doing an own Authentication (Separate Class) system for my Webshop project. My problem is, that I need conditional statement inside foreach loop, to return the code (see below).
Any suggestions?

My code currently look like this

public function regiAuth($email, $password, $firstname, $lastname)
{
    $authContainer = [$email, $password, $firstname, $lastname];
    foreach ($authContainer as $a) {
        return !empty($_POST[$a]);
    }
}

And I want to result this (With &&)

return !empty($_POST[$email]) && !empty($_POST[$password]) &&
!empty($_POST[$firstname]) && !empty($_POST[$lastname])

>Solution :

I believe you could do simply by do

foreach ($authContainer as $a) {
  if (empty($_POST[$a])
    return false;
}
return true;

instead of checking if all of them are full, you look if there is at least one empty.

it is a good practice to stop iteration if you find one element that is not as expected, imagine if you had an array of hundreads of assertions to do.