php error Function name must be a string php - php

Question

I'm building a dynamic website, but the pages are not showing up because of the error
Fatal error: Function name must be a string php
on the line
$p= $_GET('p');
The whole code for including the files is
$folder = 'de/';
$folder = 'en/';
if(!empty($_GET['p'])){
$pages = scandir($folder,0);
unset($pages[0],$pages[1]);
$p= $_GET('p');
if(in_array($p.'.inc.php', $pages)){
include($folder.'/'.$p.'.inc.php');
}else{
echo 'error message';
}
}else{
include($folder.'home.inc.php');
}
What's wrong with my code?
UPDATE
I've updated the code, but now i get the error
*failed to open stream: No such file or directory*
I'm working on a local server.

Answer 1

$p= $_GET('p');
should be
$p= $_GET['p'];

Answer 2

Your code is quite inefficient. Why slurp up the directory's contents into an array and then search the array when you could simply have:
if (isset($_GET['p']) {
$file = $folder . $_GET['p'] .'.inc.php';
if (is_readable($file)) {
include($file);
} else {
die('error');
}
} else {
include($folder.'home.inc.php');
}
This is BY FAR simpler than your convoluted logic. It is however, also vulnerable to the exact same vulnerability: you're allow the user to specify a full path to ANY *.inc.php file on your server for which they know the path name. Depending on your setup, this could allow the user to include files which you ever intended to be executed in this manner and leak internal details of your system/configuration.

Answer 3

$p= $_GET('p');
You really didn't notice that you were using parenthesis?
Use:
$p = $_GET['p'];

Answer 4

$p= $_GET('p'); it should be $p= $_GET['p'];

Answer 5

The error seems $_GET('p') should be $_GET['p'] instead.
A few considerations:
The if(!empty($_GET['p'])), could be changed to if (array_key_exists('p', $_GET) && !empty($_GET['p']) instead. PHP always complain about array indexes and it's a good way to prevent it.
on unset($pages[0],$pages[1]);, if the array doesn't return 2 elements, it will return null and PHP unset function will complain. A better way could you check if there are elements on $pages variable;
In case of scandir doesn't return any element, not sure if it'll return null or array, so in this case if(in_array($p.'.inc.php', $pages)) will throw a error.
Cheers