php 显示当前星期几 php 时间操作

<?php
echo date("Y年m月d日 H:i:s"),"<br/>";
#time 得到当前时间戳
echo date("Y年m月d日 H:i:s",time()),"<br/>";
echo time(),"<br/>";
$weekarray=array("日","一","二","三","四","五","六"); //先定义一个数组
echo "星期".$weekarray[date("w",strtotime("2018-10-25"))],"<br/>";