How can PHP beginners effectively troubleshoot and debug regular expression patterns?

When troubleshooting and debugging regular expression patterns in PHP, beginners can use online regex testers like regex101.com or regexr.com to test their patterns and see if they match the desired strings. Additionally, beginners can use functions like preg_match() or preg_match_all() in PHP to test their regular expressions within their code and see if they are working as expected.

$pattern = '/[0-9]+/';
$string = 'This is a string with numbers 12345';

if (preg_match($pattern, $string, $matches)) {
    echo 'Pattern matched!';
    print_r($matches);
} else {
    echo 'Pattern not matched.';
}