How does using strtotime() or DateTime() help in handling date and time conversions in PHP?

When working with dates and times in PHP, it can be challenging to convert between different formats or timezones. Using strtotime() or DateTime() can simplify this process by allowing you to easily parse and manipulate date and time strings. strtotime() converts a human-readable date/time string into a Unix timestamp, while DateTime() provides a more object-oriented approach for working with dates and times.

// Example using strtotime()
$dateString = '2022-01-01';
$timestamp = strtotime($dateString);
echo date('Y-m-d', $timestamp); // Output: 2022-01-01

// Example using DateTime()
$dateString = '2022-01-01';
$date = new DateTime($dateString);
echo $date->format('Y-m-d'); // Output: 2022-01-01