ACFデイトピッカーで曜日を表示

<?php $week = array("日", "月", "火", "水", "木", "金", "土"); ?>

<?php $date = date_create(''.get_field('カスタムフィールド名').''); echo date_format($date,'Y/m/d') . "(" . $week[(int)date_format($date,'w')] . ")" ; ?>