How can I limit the max value of number?

Question

I want to secure my page by checking if the value is digital (0,1,2,3) and if it is in the range from 0 to 120. I think ctype_digit function limits numbers, so

Answer 1

You might want to take a look at PHP's Data Filtering.

It provides a filter for your task (FILTER_VALIDATE_INT) which also accepts min_range and max_range parameters:

$value = filter_var($_GET['category'], FILTER_VALIDATE_INT, array(
    'options' => array(
        // An optional default value
        'default' => 123,

        // Desired validation range
        'min_range' => 0,
        'max_range' => 120
    ),
));

// $value is FALSE when validation failed, or an "int" with
// the correct value.

Answer 2

if(!ctype_digit($_GET['category']) || $_GET['category'] > 120) {
...

Answer 3

if(!ctype_digit($_GET['category']) || $_GET['category'] > 120) //do whatever you want

Answer 4

Not an answer, but here's why what you had wouldn't work:

if (!ctype_digit($_GET['category'] > 120) ?
                 ^^^^^^^^^^^^^^^^^^^^^^^

The indicated part is inside the ctype call. So first PHP will check if the GET value is greater than 120, turning that into a boolean true/false. THEN the ctype is applied, which will always be false, as a boolean value is not a digit.

Answer 5

// Make sure it is an integer.
$category = (int) $_GET['category'];

if($category<0 OR $category>120){
   // Code to be executed if the number is out of range...
}

Answer 6

Here's a simple way:

function set_range($value, $minimum, $maximum) {
    return min(max($minimum, $value), $maximum);
}

Here's what we're doing:

1. compare the number with our minimum value, and take the highest number.
2. compare that result with our maximum value, and take the lowest number.

And here's a test:

// Check every fifth number between 0-60 and 
// set output to within range of 20 to 40.
//
for ($i = 0; $i < 60; $i += 5) {
    echo $i . " becomes " . set_range($i, 20, 40) . PHP_EOL;
}

If you want to check if a number is within a range, you could do this:

function in_range($value, $minimum, $maximum) {
   return ($value >= $minimum) && ($value <= $maximum);
}

echo (in_range( 7, 20, 40)) ? "yes" : "no";  // output: no
echo (in_range(33, 20, 40)) ? "yes" : "no";  // output: yes