What is the correct way to determine the calendar week of a specific date using PHP date functions?

To determine the calendar week of a specific date in PHP, you can use the "W" format character in the date() function. This character will return the ISO-8601 week number of the year for the given date.

$date = "2022-10-15"; // Specific date
$week = date("W", strtotime($date)); // Get the calendar week number
echo "The calendar week of $date is week $week.";