week day to number or visa versa

daynumber.php

<?php

       function dayToNumber($day) {
            $array = array('Mon' => 1, 'Tue' => 2, 'Wed' => 3, 'Thu' => 4, 'Fri' => 5, 'Sat' => 6, 'Sun' => 7);
            $result = $array[$day];
            return $result;
        }

        function numberToDay($number) {
            $array = array(1 => 'Mon', 2 => 'Tue', 3 => 'Wed', 4 => 'Thu', 5 => 'Fri', 6 => 'Sat', 7 => 'Sun');
            $result = $array[$number];
            return $result;
        }