majuk

In the lesson on PHP Filters in the code sample "Validate an Integer" there is the following code:

<?php
$int = 100;

if (!filter_var($int, FILTER_VALIDATE_INT) === false) {
    echo("Integer is valid");
} else {
    echo("Integer is not valid");
}
?> 

Why use this expression:

(!filter_var($int, FILTER_VALIDATE_INT) === false)

instead of what seems to me to be the more logical expression?:

  (filter_var($int, FILTER_VALIDATE_INT) === true)

Thanks.