Function that returns only numbers?

Question

function get_only_numbers($string){
    $getonly = str_split("0123456789");
    $string = str_split($string);
    foreach($string as $i => $c){
        if(!in_array($c, $getonly))
            unset($string[$i]);
    }
    return implode("", $string);
}

echo get_only_numbers("U$ 499,50"); // prints 49950

This function is supposed to return only the numbers from a string. Has this function been coded properly?

Answer 1

I think a single call to preg_replace can do that as well:

preg_replace('/\D+/', '', 'U$ 499,50'); // returns "49950"

Answer 2

See is_numeric to further optimize your function so that you don't need the array comparison.