What are some common errors or issues that may occur when implementing preg_replace_callback in PHP?

One common issue when implementing preg_replace_callback in PHP is not passing the correct arguments to the callback function. Make sure to include the $matches parameter in your callback function to access the matched groups from the regular expression pattern. Additionally, ensure that your callback function returns the replacement string.

// Incorrect implementation
$string = "Hello, World!";
$pattern = "/Hello/";
$new_string = preg_replace_callback($pattern, function($match) {
    return "Goodbye";
}, $string);

// Correct implementation
$string = "Hello, World!";
$pattern = "/Hello/";
$new_string = preg_replace_callback($pattern, function($match) {
    return "Goodbye";
}, $string);