Simplifying PHP if's and arrays - php

Question

I have a piece of code I just wrote that detects if there is a user logged in and if [1] and [2] have any specific text in the string and then will relocate that person to another page if the values are met.
But I think my code is a little long winded. Is there a way to simplify what I have or is this the best I'll get?
if (!isset($_SESSION['user_id'])){
$dir = dirname($_SERVER['PHP_SELF']);
$dirs = explode('/', $dir);
if(isset($dirs[1])){
if (($dirs[1] == "account") || ($dirs[1] == "admin")){
header('Location: /');
}
}
if(isset($dirs[2])){
if(($dirs[2] == "account")){
header('Location: /');
}
}
}
Thanks in advance

Answer 1

a simple way is to use a closure
$dir = explode('/', dirname($_SERVER['PHP_SELF']));
$is = function($pos, $check) use($dir) {
return array_key_exists($pos, $dir) && $dir[$pos] == $check;
};
if($is->__invoke(1, 'account')
|| $is->__invoke(1, 'admin')
|| $is->__invoke(2, 'account')) {
header('Location: /');
}

Answer 2

You could do that for instance:
$dir = dirname($_SERVER['PHP_SELF']);
$dirs = explode('/', $dir);
if(in_array('account',$dirs) || in_array('admin', $dirs)){
header('Location: /');
}

Answer 3

One of a few simpler solutions could be to use PHP's array_intersect($array1, $array2) function. This is well documented on the php.net website, but here's a little example:
// Define all the 'search' needles
$needles = array('account', 'admin');
// Get all the dirs
$dirs = explode('/', dirname( $_SERVER['PHP_SELF'] ));
// Check for needles in the hay
if( array_intersect($needles, $dirs) )
{
// Redirect
header('Location: /');
}
ADDED: You could of course make the above very simple by combining multiple lines into one, this would leave you with:
if( array_intersect(array('account', 'admin'), explode('/', dirname($_SERVER['PHP_SELF']))) )
{
header('Location: /');
}