Returns an array of dates for the day of the week between two date ranges

getDatesForSpecificDayBetweenDates.php

<?php
/**
 * Returns an array of dates for the day of the week between two date ranges
 * Modified from stackoverflow question and improved for broader usage
 * @link http://stackoverflow.com/a/4482605/650206
 * @param string|int $startDate
 * @param string|int $endDate
 * @param int $weekdayNumber
 * @param string $dateFormat
 * @param string $dateWeekNumberFormat  w: 0 (sunday) - 6 (saturday) | N: 1 (monday) - 7 (sunday)
 * @return array
 */
function getDatesForSpecificDayBetweenDates($startDate, $endDate, $weekdayNumber, $dateFormat='Y-m-d', $dateWeekNumberFormat='w') {
    // Fix the proper date range, if needed  (prevents issues with int in strtotime)
    $startDate = !is_int($startDate) ? strtotime($startDate) : $startDate;
    $endDate = !is_int($endDate) ? strtotime($endDate) : $endDate;
    // Move start date to the proper $weekDayNumber
    do {
        if (date($dateWeekNumberFormat, $startDate) != $weekdayNumber) {
            $startDate += (24 * 3600); // add 1 day
        }
    } while (date($dateWeekNumberFormat, $startDate) != $weekdayNumber);
    // Build dates array
    $dateArr = array();
    while ($startDate <= $endDate) {
        $dateArr[] = date($dateFormat, $startDate);
        $startDate += (7 * 24 * 3600); // add 7 days
    }
    return ($dateArr);
}