PHP自定义函数--输入起始日期和解算日期返回日期差几天和 上一个周期的起始结束日期

/** 日期差几天* @param beginDate:2018-01-26 endDatee:2018-01-26* @return int days* */
function dateDiff($beginDate, $endDate)
{$diff = date_diff(date_create($beginDate), date_create($endDate))->format('%R%a');return (int)$diff;
}/** 返回上一周期的起始和结束日期和差几天* @param beginDate:2018-01-26 endDatee:2018-01-26* @return array* */
function dateBeginEnd($beginDate, $endDate)
{$diff = (int)date_diff(date_create($beginDate), date_create($endDate))->format('%R%a');$dateDiff = dateDiff($beginDate,$endDate)+1;$startDate = date('Y-m-d',strtotime($beginDate)-$dateDiff*24*3600);$endDate = (date('Y-m-d',strtotime($startDate)+($dateDiff-1)*24*3600));return ['beginDate'=>$startDate,'endDate'=>$endDate,'diff'=>$diff];
}