What are the recommended delimiter characters for regular expressions in PHP to maintain code clarity and consistency?

Using consistent and clear delimiter characters in regular expressions in PHP can help maintain code clarity and consistency. It is recommended to use characters that are not commonly found in the regular expression itself to avoid confusion. Common delimiter characters include forward slashes (/), hash symbols (#), and tildes (~). By using consistent delimiter characters throughout your regular expressions, you can make your code more readable and easier to maintain.

$pattern = '/^Hello, world$/'; // Using forward slashes as delimiter