怎么获得一段时间内的完整星期的数量SegmentFault

function get_weekend_days($start, $end) {
    $days = (strtotime($end) - strtotime($start)) / 86400;
    return floor($days / 7);
}

echo get_weekend_days('2014-02-03', '2015-12-28');

<?php
/*  作用由起止日期算出其中的周
 *  @param start_date 开始日期
 *  @param end_date   结束日期
 *  @return 返回二维数组，含每周起止时间
 *  @author anngly
 *  @modify for segmentfault
 *  注意：end_date>state_date
 **/
function getWeek($start_date, $end_date)
{
    //设定每周开始时间  monday-sunday
    $week_start = "monday";
    //设定返回时间格式
    $date_format = "Ymd";
    $start_date = strtotime($start_date);
    $end_date = strtotime($end_date);
    if ($start_date <= $end_date) {
        $end_date = strtotime("last ".$week_start, $end_date);
        $start_date = date("w", $start_date) == 1 ? $start_date : strtotime("next ".$week_start, $start_date);
        $count_week = ($end_date - $start_date) / (7 * 24 * 3600);
        for ($i = 0; $i < $count_week; $i++) {
            $sd = date($date_format, $start_date);
            $ed = strtotime("+ 6 days", $start_date);
            $eed = date($date_format, $ed);
            $arr[] = array($sd, $eed);
            $start_date = strtotime("+ 1 day", $ed);

            //输出测试
            echo "第 ".($i + 1)." 周<br>";
            echo "开始".$sd."<br>";
            echo "结束".$eed."<br>";
        }
        return $arr;
    }
}
var_dump(getWeek("20160101", "20160120"));
?>

第 1 周
开始20160104
结束20160110
第 2 周
开始20160111
结束20160117
array(2) { [0]=> array(2) { [0]=> string(8) "20160104" [1]=> string(8) "20160110" } [1]=> array(2) { [0]=> string(8) "20160111" [1]=> string(8) "20160117" } }

DatePeriod

in_array(date('w', strtotime($date)), [0, 6])

strtotime('next monday');