How can PHP be used to differentiate between past and future events in a list?

To differentiate between past and future events in a list using PHP, you can compare the event dates with the current date. If the event date is in the past, you can display it differently than if it is in the future. You can use the PHP `strtotime()` function to convert the event date to a timestamp and then compare it with the current timestamp obtained using `time()`.

$current_date = time();

$event_date = strtotime('2022-12-31');

if ($event_date < $current_date) {
    echo "Past Event: " . date('Y-m-d', $event_date);
} else {
    echo "Future Event: " . date('Y-m-d', $event_date);
}