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<?php $weekdays = array("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"); $mydays = array("Monday", "Tuesday", "Thursday", "Friday", "Saturday", "Sunday"); $missingDay = array_diff($weekdays, $mydays); print_r($missingDay);
Output for 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.30, 8.4.1 - 8.4.18, 8.5.0 - 8.5.3
Array ( [2] => Wednesday )

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