In PHP, how do I validate strings with PHP 8+ features?

In PHP 8 and later, there are several modern features you can use to validate strings effectively. One of the most common methods is using the built-in filter functions and the new match expression. Additionally, you can leverage named arguments for better clarity. Here's an example of how to perform string validation.


         false,
                !preg_match('/^[a-zA-Z]+$/', $input) => false,
                default => true,
            };
        }

        $stringToValidate = "TestString";
        if (validateString($stringToValidate)) {
            echo "{$stringToValidate} is a valid string.";
        } else {
            echo "{$stringToValidate} is not a valid string.";
        }
        ?>