Are there any specific resources or tools recommended for testing regular expressions in PHP applications?

Regular expressions can be complex and difficult to debug, so it's important to have tools to test them effectively. One recommended tool for testing regular expressions in PHP applications is an online regex tester like regex101.com or regexr.com. These tools allow you to input your regular expression and test it against sample strings to see if it matches correctly.

$regex = "/[0-9]{3}-[0-9]{3}-[0-9]{4}/"; // Regular expression to match a phone number in the format XXX-XXX-XXXX
$string = "123-456-7890"; // Sample phone number to test against the regular expression

if (preg_match($regex, $string)) {
    echo "Phone number is valid!";
} else {
    echo "Phone number is not valid.";
}