PHP How do I "global variable" in an array?

Question

Global variable can't be read on my function. Anyone know what's wrong with my code below? Please help me.

<?php
global $a = array(2,3,4); 
global $b = array(3,5,6); 

function test(){
        $y = $a[0]*$b[0];
        return $y;
}
test();
?>

Answer 1

<?php
$a = array(2,3,4); 
$b = array(3,5,6); 

function test(){
GLOBAL $a;
GLOBAL $b;
        $y = $a[0]*$b[0];
        return $y;
}
test();
?>

Answer 2

It seems you have some misconception regarding the global variables.

You don't declare the variables as global ..instead you tell php that you want to use the use the variable that is not in scope of function

So your code will be

<?php
  $a = array(2,3,4); 
  $b = array(3,5,6); 

function test()
{
    global $a, $b;
    $y = $a[0]*$b[0];
    // or you can use $GLOBAL['a'][0] * $GLOBAL['b'][0]
    return $y;
 }
echo test();
 ?>

Now with this code you are saying that use variables $a and $b that are defined outside the scope of function.

DOCUMENTATION

Hope it helps you and you understand what I want to say

Answer 3

First you have to declare the global.

global $a;

Then you can make it an array.

$a = array(2,3,4);

Also, if you're using a function. Declare global inside the function, not outside of it.

<?php
$a = array(2,3,4); 
$b = array(3,5,6); 

$output = test($a,$b);
echo $output;

function test($array1,$array2)
{
$y = $array1[0]*$array2[0];
return $y;
}
?>

Here's an explanation for you. Where we have:

function test($array1,$array2)

We are saying that any value that is put in those spots when the function is called is treated as $array1 and $array2 INSIDE the function.

So when we call it we say test($a,$b) So when the function runs $array1 == $a, and $array2 == $b.

Inside the function the variables $a and $b basically becomes $array1 and 2.

The return value makes the function call basically be the equivalent of that return outside of the function so that:

$output = test($a,$b);

Is exactly like saying:

$output = 6;

I hope that helps.

Answer 4

Use the global keyword to include a variable in scope.

Here's how it would look with the snippet you provided.

$a = array(2, 3, 4); 
$b = array(3, 5, 6); 

function test() {
    // include $a and $b in the scope of this function.
    global $a, $b;

    $y = $a[0] * $b[0];

    return $y;
}

Visit the documentation link provided above to see more syntax of the global keyword.

You can additionally use the $GLOBALS array to access a and b.

$y = $GLOBALS['a'][0] * $GLOBALS['b'][0];