php计算一年多少周 同时计算出这一周的开始时间和结束时间（可选返回时间戳或日期）

functiongetWeekStartAndEnd($year,$week=1){header("Content-type:text/html;charset=utf-8"); date_default_timezone_set("Asia/Shanghai"); $year=(int)$year; $week=(int)$week; //按给定的年份计算本年周总数 $date=newDateTime; $date->setISODate($year,53); $weeks=max($date->format("W"),52); //如果给定的周数大于周总数或小于等于0 if($week>$weeks||$week<=0){returnfalse; } //如果周数小于10 if($week<10){$week='0'.$week; } //当周起止时间戳 $timestamp['start']=strtotime($year.'W'.$week); $timestamp['end']=strtotime('+1week-1day',$timestamp['start']); //当周起止日期 $timeymd['start']=date("Y-m-d",$timestamp['start']); $timeymd['end']=date("Y-m-d",$timestamp['end']); //返回起始时间戳 return$timestamp; //返回日期形式 //return$timeymd; }