altering variable within function, how to make altered variable global?

helz

i have a function that alters the data inside an array, now this works fine, but how do i make this affect the array outside the function? do i just do a return value? eg:

$array = array(1,2,3,4);
$array = AlterArray($array);

herve

You have to declare the variable as "global" inside the fonction, that is :

<?PHP

function AlterArray()
{
    global $myarray;

// do what I want with the array here
}

$myarray = array (1,2,3,4);

AlterArray();

foreach ($myarray as $num)
{
    print $num;
}

?>

or if you have to pass the variable as a parameter (so you can't use the 'global ' directive) :

<?PHP

function AlterArray($var)
{

$GLOBALS[$var];  // Reference your var at a global level

// do what I want with the array here
}

$myarray = array (1,2,3,4);

AlterArray($myarray);

foreach ($myarray as $num)
{
    print $num;
}

?>

helz

yeh, looks like ill have to stick with the return value, since the arrays going into the function will have different labels:
ie:

function AlterArray($array) {
foreach ($array as $value)
$value++;
return $array;
}

$arr1 = {1,2,3,4};
$arr1 = AlterArray($arr1);

thanks anyway
just one more thing

i thought the global $variable
was to get a variable from outside (global) into the function (local)
can it be used to set local variables to global ones?

Installer

Or you can pass by reference:

function AlterArray(&$inside_array)
{
    $inside_array['key'] = 'new value';
}

$outside_array = array('key' => 'old value');
echo $outside_array['key'] . '<br />';
AlterArray($outside_array);
echo $outside_array['key'];

You can assign function variables to " $_GLOBAL[]", but you can't use them with "global".

helz

that reference sounds grand!

thanks again!
just to confirm.
the & points to the location of a variable that superceeds it? instead of creating a new variable?

ie:

function GetVar(&$variable) {
    $variable *= 2;
}
$var = 3;
echo $var;//give 3
GetVar($var);
echo $var;//give 6

Installer

The two variables are "pointing to the same place". That is, they are two separate variables that share the same value storage memory.

helz

ah, that makes sense!
i had some code that used pointers before, but didnt quite understand it, thanks for clearing that up!

Installer

They're not pointers, like in some other languages, but references. They work slightly differently.