How can PHP functions like strrpos and substr be effectively used for manipulating strings with variable content?

When manipulating strings with variable content in PHP, functions like strrpos and substr can be effectively used to locate specific characters within a string and extract substrings based on their positions. strrpos can be used to find the last occurrence of a specific character in a string, while substr can then be used to extract a substring starting from that position.

// Example of using strrpos and substr to manipulate strings with variable content

$string = "Hello, World!";
$lastCommaPosition = strrpos($string, ",");
if ($lastCommaPosition !== false) {
    $newString = substr($string, $lastCommaPosition + 1);
    echo $newString; // Output: World!
}