Question

I’m hoping someone could give me some input on how to improve this function. Its purpose is to evaluate whether a form input is a valid integer, and if not, either return a zero by default, or -1 if the second argument = true.

EDIT: Here is an updated version of the function I’m using. It seems the two most challenging parts are to ensure that an empty string doesn’t evaluate as 0 when expecting -1 for empty strings ($neg=true), and evaluating inputs with left padded zeros as integers and not octals.

function clean_integer($value, $neg=false) 
{
    if (!is_numeric($value)) {
        if (!$neg) {
            return 0;
        else {
            return -1;
        }
    }
    $value = ltrim(trim($value), '0');
    if (!$neg) 
    {
        if ($value !== true && ((string)(int) $value) === ((string) $value)) {
            return (int) $value;
        }
        else {
            return 0;
        }
    }
    else
    {
        if (!is_numeric($value)) {
            return 0;
        }
        if ($value !== true && ((string)(int) $value) === ((string) $value)) {
            return (int) $value;
        }
        else {
            return -1;
        }        
    }
}

I’ve been staring at this for too long and am convinced I’m making it terribly overcomplicated.

Answer 1

Why not cast it and use the is_int() method? – http://php.net/manual/en/function.is-int.php

$num = (int) $theNumber;
echo is_int($num);

To adapt it to your function

function clean_integer($value, $neg=false) { 
   $num = $value; //removed the cast
   if (!is_int($num)) {
     return ($neg) ?  -1 : 0;     
   } 
   return $num;
}