using a function irrespective of the argument being an array or a string

[lajkonik86]

i would like to run a function on a variable but im not sure whether it will be an array or a string.
What is the most effective way of doing this?

say to run trim() on every value in the array or if it is not an array on the string itself.

[laserlight]

Well, one possibility is to make use of is_array:

function trimAll($input) {
    if (is_array($input)) {
        foreach ($input as $key => $value) {
            $input[$key] = trimAll($value);
        }
    } else {
        $input = trim($input);
    }
    return $input;
}

[NogDog]

For the stated example purpose, I'd probably stick with what Laserlight suggested. For more complex functions, I might consider converting any string into a single element array:

function example($arg)
{
   $myArray = (is_array($arg)) ? $arg : array($arg);
   // from this point forward, work with $myArray...
   array_walk($myArray, create_function('&$val, $key', 'trim($val);'));
   sort($myArray);
   // etc....
}