php function variable scope

Question

I was wondering if i have a function like this:

function isAdmin ($user_id) {

    $admin_arr = array(1, 2);

    foreach ($admin_arr as $value) {

        if ($value == $user_id) {
            return true;
        }
    }

    return false;
}

Could i make an array outside of that function as a global array and use it inside the function without sending it through as a parameter, also instead declaring a new admin array inside the function as i just did above? How would i do this?

Regards, Alexander

Answer 1

To answer literal question:

// Global variable
$admin_arr = array(1, 2);

function isAdmin ($user_id) {

    // Declare global
    global $admin_arr;

    foreach ($admin_arr as $value) {

        if ($value == $user_id) {
            return true;
        }
    }

return false;
}

Documentation here: http://php.net/manual/en/language.variables.scope.php

To answer the REAL question: Avoid global at all costs. You are introducing a plethora of error prone code into your application. Relying on global variables is entering a world of pain and makes your functions less useful.

Avoid it unless you absolutely see no other way.

Answer 2

you have to do this with the global keyword

here an example

$arr = array('bar');
function foo() {
    global $arr;
    echo array_pop($arr);
}
foo();