如何在PHP中找到当前月份的最后一个星期六是哪一天?

Question

这适用于大多数月份，但例如，2011年4月有5个星期六，因此返回23而不是30。

$last_saturday = date("j", strtotime('Fourth Saturday'.date('F o')));

Answer 1

有趣的是，strtotime("last saturday of this month")正是这样做的。

请参阅支持的日期和时间格式了解更多信息，特别是有关相对格式的部分。

Answer 2

last saturday似乎在某些星座中被解释为"上星期六"。

这是我在Windows 7上的PHP 5.3上的工作:跳转到下个月的第一天，并查找上周六。

 $nextMonthStart = mktime(0,0,0,date('m')+1,1,date('Y'));
 $last_saturday = date("d.m.Y",strtotime("previous saturday", $nextMonthStart));

即使在下个月的第一天是星期六这种极端情况下也适用。

Answer 3

现在人们太随意地使用strtotime了…如果您想成为真正的硬核(并重新发明轮子)，您可以使用我当年为Moodle编写的这段代码，我猜它具有一些新奇的价值。我从这里复制过来的。

2011年4月的最后一个星期天是find_day_in_month(-1, 0, 4, 2011)，意思是"从2011年4月的最后一天开始向后搜索，告诉我你找到的第一个星期天是什么时候"。

实际操作

/**
 * Calculate the number of days in a given month
 *
 * @param int $month The month whose day count is sought
 * @param int $year The year of the month whose day count is sought
 * @return int
 */
function days_in_month($month, $year) {
   return intval(date('t', mktime(12, 0, 0, $month, 1, $year)));
}

/**
 * ?
 *
 * @todo Document what this function does
 * @param int $startday Defines the day from which to start searching (absolute value) and the direction in which to search (sign)
 * @param int $weekday -1 if you don't want the function to match a specific weekday; 0 to 6 to match specific weekdays
 * @param int $month The month wherein the day is sought
 * @param int $year The year wherein the day is sought
 * @return int
 */
function find_day_in_month($startday, $weekday, $month, $year) {
    $daysinmonth = days_in_month($month, $year);
    if($weekday == -1) {
        // Don't care about weekday, so return:
        //    abs($startday) if $startday != -1
        //    $daysinmonth otherwise
        return ($startday == -1) ? $daysinmonth : abs($startday);
    }
    // From now on we 're looking for a specific weekday
    // Give "end of month" its actual value, since we know it
    if($startday == -1) {
        $startday = -1 * $daysinmonth;
    }
    // Starting from day $startday, the sign is the direction
    if($startday < 1) {
        $startday = abs($startday);
        $lastmonthweekday  = strftime('%w', mktime(12, 0, 0, $month, $daysinmonth, $year));
        // This is the last such weekday of the month
        $lastinmonth = $daysinmonth + $weekday - $lastmonthweekday;
        if($lastinmonth > $daysinmonth) {
            $lastinmonth -= 7;
        }
        // Find the first such weekday <= $startday
        while($lastinmonth > $startday) {
            $lastinmonth -= 7;
        }
        return $lastinmonth;
    }
    else {
        $indexweekday = strftime('%w', mktime(12, 0, 0, $month, $startday, $year));
        $diff = $weekday - $indexweekday;
        if($diff < 0) {
            $diff += 7;
        }
        // This is the first such weekday of the month equal to or after $startday
        $firstfromindex = $startday + $diff;
        return $firstfromindex;
    }
}

Answer 4

https://github.com/briannesbitt/carbon

<?php
require 'vendor/autoload.php';
use CarbonCarbon;
$date = Carbon::now();
$date = $date->lastOfMonth(Carbon::SATURDAY);
echo 'last saturday = '.$date->day;

Answer 5

$lastSaturDay= date('Y-m-d'， strtotime('本月最后一个星期六'));