What are some best practices for passing arrays in PHP functions, such as returning them, using references, or declaring them as global variables?

When passing arrays in PHP functions, it is best practice to use references if you want to modify the original array within the function. This ensures that changes made to the array inside the function are reflected outside of it. Alternatively, you can return the modified array from the function to avoid side effects. Avoid declaring arrays as global variables unless absolutely necessary, as it can lead to unexpected behavior and make the code harder to maintain.

// Pass array by reference to modify original array
function modifyArray(&$array) {
    $array[] = 'new element';
}

$array = [1, 2, 3];
modifyArray($array);
print_r($array);

// Return modified array from function
function modifyArray($array) {
    $array[] = 'new element';
    return $array;
}

$array = [1, 2, 3];
$array = modifyArray($array);
print_r($array);