Are there any best practices for handling string manipulation in PHP?

When handling string manipulation in PHP, it is best to use built-in functions such as `strlen()`, `substr()`, `str_replace()`, and `explode()` to efficiently manipulate strings. It is also important to sanitize user input to prevent security vulnerabilities such as SQL injection. Additionally, consider using regular expressions when dealing with complex string patterns.

// Example of sanitizing user input
$userInput = $_POST['user_input'];
$sanitizedInput = htmlspecialchars($userInput);

// Example of getting the length of a string
$string = "Hello, World!";
$length = strlen($string);

// Example of replacing a substring in a string
$newString = str_replace("World", "PHP", $string);

// Example of splitting a string into an array
$words = explode(" ", $string);