is_int and GET or POST

Question

Why does is_int always return false in the following situation?

echo $_GET[\'id\']; //3
if(is_int($_GET[\'id\']))
    echo \'int\'; //not execut         


        

Answer 1

Prabably best way to check if value from GET or POST is integer is check by preg_match

if( preg_match('/^[0-9]+$/', $_GET['id'] ){
   echo "is int";
}

Answer 2

Why does is_int always return false?

Because $_GET["id"] is a string, even if it happens to contain a number.

Your options:

• Use the filter extension. filter_input(INPUT_GET, "id", FILTER_VALIDATE_INT) will return an integer typed variable if the variable exists, is not an array, represents an integer and that integer is within the valid bounds. Otherwise it will return false.

• Force cast it to integer (int)$_GET["id"] - probably not what you want because you can't properly handle errors (i.e. "id" not being a number)

• Use ctype_digit() to make sure the string consists only of numbers, and therefore is an integer - technically, this returns true also with very large numbers that are beyond int's scope, but I doubt this will be a problem. However, note that this method will not recognize negative numbers.

Do not use:

• is_numeric() because it will also recognize float values (1.23132)

Answer 3

You can possibly try the intval() which can be used to test the value of your var. e.g

If(intval($_GET['ID']==0)

The function will check if the var is integer and return TRUE if not FALSE

Answer 4

The dirty solution I'm using is this:

$val = trim($_GET['id']);
$cnd = ($val == (int)$val);
echo $cnd ? "It's an int" : "Not an int";

Apart from the obvious (ugly code that hides its workings behind specifics of the php engine), does anybody know cases where this goes wrong?