Use Array From Function 1 in Function 2

I have a (simplified) function that uses开发者_开发知识库 in_array() to check if a value is in an array:

function is($input) {
    $class = array('msie','ie','ie9');
    $is = FALSE;
    if (in_array($input, $class)) {$is = TRUE;}
    return $is;
}

if (is('msie')) 
    echo 'Friends don\'t let friends use IE.';

I want to break this into two separate functions, where the first defines the array:

   function myarray() {
        $class = array('msie','ie','ie9');
    }

and the second runs the check—either like this:

function is($input) {
    myarray();
    $is = FALSE;
    if (in_array($input, $class)) {$is = TRUE;}
    return $is;
}

Or this:

function is($input) {
    global $class;
    $is = FALSE;
    if (in_array($input, $class)) {$is = TRUE;}
    return $is;
}

But both of the above cause this error:

Warning: in_array() [function.in-array]: Wrong datatype for second argument in /home/vanetten/temp.ryanve.com/PHP/airve.php on line 73

What is the proper way use an array from one function in another? Can an array be a global variable? How do I make this work? Is it more efficient to use a global variable or to call the first function within the second function. Any help is definitely appreciated.

Return the array from the first function:

function myarray() {
    return array('msie','ie','ie9');
}

function is($input) {
    $array = myarray();
    return in_array($input, $array);
    // or even just
    // return in_array($input, myarray());
}

function is($input) {
  $class = myarray();
  $is = false;
  ...

Easiest way (which also negates the use of global variables, which is a bad practice since using $class somewhere else down the line may result in unexpected behavior) is something like

function myarray() {
    return array('msie','ie','ie9');
}

function is($input) {
    $array = myarray();
    $is = FALSE;
    if (in_array($input, $array)) {$is = TRUE;}
    return $is;
}

if (is('msie')) 
    echo 'Friends don\'t let friends use IE.';

In this example, we just make myarray() return the needed array. In is(), add the line $array = myarray(), which will save the array from myarray(), so it is useable from is() as the alias $array. Then simply change $class to $array, and it should work fine.