php怎么获取日期是当月第几周

<?php
$time = strtotime('2019-01-01');
$wk_day = date('w', strtotime(date('Y-m-1 00:00:00', $time))) ? : 7; //今天周几
$day = date('d', $time) - (8 - $wk_day); //今天几号
echo $day <= 0 ? 1 : ceil($day / 7) + 1; //计算是第几个星期
 
print_r(week_of_month(strtotime('2019-01-1')));
 
function week_of_month($time, $offset = 1){
        $week = get_week_block($time);
        $wk_day = date('w', strtotime(date('Y-m-1 00:00:00', $time))) ? : 7; //今天周几
        $day = date('d', $time) - (8 - $wk_day); //今天几号
        $weekof = $day <= 0 ? 1 : ceil($day / 7) + 1; //计算是第几个星期
        if($offset){
            $week[0] = date('Y-m-d', max(strtotime(date('Y-m-1 00:00:00', $time)), $week[0]));
            $week[1] = date('Y-m-d', min(strtotime(date('Y-m-'.date('t', $time).' 23:59:59', $time)), $week[1]));
        }else{
            $week[0] = date('Y-m-d', $week[0]);
            $week[1] = date('Y-m-d', $week[1]);
        }
        return ['week' => $week, 'weekof' => $weekof];
}
 
function get_week_block($sdefaultDate = false, $first = 1){
//当前日期    
//$first =1 表示每周星期一为开始日期 0表示每周日为开始日期  
if(!$sdefaultDate)$sdefaultDate = time();
if(is_numeric($sdefaultDate))$sdefaultDate = date('Y-m-d', $sdefaultDate);
//获取当前周的第几天 周日是 0 周一到周六是 1 - 6  
$w=date('w', strtotime($sdefaultDate));  
//获取本周开始日期，如果$w是0，则表示周日，减去 6 天  
$week_start=date('Y-m-d',strtotime("$sdefaultDate -".($w ? $w - $first : 6).' days'));  
//本周结束日期  
$week_end=date('Y-m-d',strtotime("$week_start +6 days"));
return array(strtotime($week_start.' 00:00:00'), strtotime($week_end.' 23:59:59'));
}