指定日付の曜日を日本語表示

コード

$dateTimeObjS = new DateTime($topicAry['start_date']);
$dateTimeObjE = new DateTime($topicAry['end_date']);
$dayWeekAry = ["日", "月", "火", "水", "木", "金", "土"];
$startDateDayWeek= $dayWeekAry[$dateTimeObjS->format('w')];
$endDateDayWeek= $dayWeekAry[$dateTimeObjE->format('w')];
(<?php echo $startDateDayWeek; ?>) ～ (<?php echo $endDateDayWeek; ?>)