分享一段php获取任意时间的前一天代码

<?php /** * 获取给定日期的前一天 * @param string $date * @return string $yesterday */function getYesterday($date){    if(empty($date))    {        $yesterday = date("Y-m-d",strtotime("-1 day"));    }else{        $arr = explode('-', $date);        $year = $arr[0];        $month = $arr[1];        $day = $arr[2];        $unixtime = mktime(0,0,0,$month,$day,$year)-86400;        $yesterday = date('Y-m-d',$unixtime);    }    return $yesterday;}