What are the best practices for using regular expressions in PHP code?

When using regular expressions in PHP code, it is important to follow best practices to ensure efficient and secure pattern matching. Some best practices include using the preg_match() function for pattern matching, escaping special characters with preg_quote() to prevent injection attacks, and using delimiters appropriately for readability. Additionally, it is recommended to use the /u modifier for Unicode support when working with multibyte characters.

// Example of using preg_match() function for pattern matching
$email = "john.doe@example.com";
if (preg_match("/^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/", $email)) {
    echo "Valid email address";
} else {
    echo "Invalid email address";
}