What are the implications of memory management in PHP, particularly when dealing with long-running scripts and object-oriented programming?

Memory management in PHP is crucial when dealing with long-running scripts and object-oriented programming to prevent memory leaks and improve performance. One way to optimize memory usage is by explicitly freeing up memory when it is no longer needed, especially in loops or when working with large datasets.

// Example of explicitly freeing memory in PHP
$data = []; // large dataset
foreach ($data as $item) {
    // process $item
    unset($item); // free memory after processing each item
}