How to pass an array into a function, and return the results with an array

Question

So I'm trying to learn how to pass arrays through a function, so that I can get around PHP's inability to return multiple values. Haven't been able to get anything to work so far, but here is my best try. Can anybody point out where I'm going wrong?

function foo($array)
{
    $array[3]=$array[0]+$array[1]+$array[2];
    return $array;
}

$waffles[0]=1;
$waffles[1]=2;
$waffles[2]=3;
foo($waffles);

echo $waffles[3];

For clarification: I want to be able to pass multiple variables into a function, do something, then return multiple variables back out while keeping them seperate. This was just an example I was trying to get working as a work around for not being able to return multiple variables from an array

Answer 1

You seem to be looking for pass-by-reference, to do that make your function look this way (note the ampersand):

function foo(&$array) {     $array[3]=$array[0]+$array[1]+$array[2]; } 

Alternately, you can assign the return value of the function to a variable:

function foo($array) {     $array[3]=$array[0]+$array[1]+$array[2];     return $array; }  $waffles = foo($waffles) 

Answer 2

You're passing the array into the function by copy. Only objects are passed by reference in PHP, and an array is not an object. Here's what you do (note the &)

function foo(&$arr) { # note the &
  $arr[3] = $arr[0]+$arr[1]+$arr[2];
}
$waffles = array(1,2,3);
foo($waffles);
echo $waffles[3]; # prints 6

That aside, I'm not sure why you would do that particular operation like that. Why not just return the sum instead of assigning it to a new array element?

Answer 3

function foo(Array $array)
{
     return $array;
}