CODEWITHSUNDEEP
php
Lucas
Lucas

Reputation: 2984

How can I limit the max value of number?

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 can not be passed any negative number. How can I limit the max value in the simplest way?

if (!ctype_digit($_GET['category'] AND ...) die('');

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

I was thinkig about intval but it can pass negative numbers.

Upvotes: 5

Views: 13041

Answers (9)

pbarney
pbarney

Reputation: 2853

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

Upvotes: 3

John
John

Reputation: 7826

I am adding this as some people might stumble here on the search for a way to this task based on the topic of your question.
Sometimes you just want to "limit the max value of a numeric variable". 

$val=($val <= 120)?$val:120;

That's the best way I found within one line (a combination of min() and max() can do the same but it's much more calculation intense) If the $val is larger than 120 it will be trimmed to 120, otherwise the original value is used.

Upvotes: 1

penartur
penartur

Reputation: 9912

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

Upvotes: 0

Tom van der Woerdt
Tom van der Woerdt

Reputation: 29975

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

Basically this says "If it's not a number or if it's larger than 120, stop"

Upvotes: 4

Linus Kleen
Linus Kleen

Reputation: 34622

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.

Upvotes: 7

Marc B
Marc B

Reputation: 360572

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.

Upvotes: 0

Tom Will
Tom Will

Reputation: 361

// 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...
}

Upvotes: 0

lamplightdev
lamplightdev

Reputation: 2071

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

Upvotes: 0

OptimusCrime
OptimusCrime

Reputation: 14863

if (is_int($_GET['category']) and $_GET['category'] > 0 and $_GET['category'] <= 120)

This will check if the number is greater than zero and smaller or equal to 120.

Upvotes: 0

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