如何在php中获得最后4周的日期(周一和周日)？

Question

我试图使用PHP的Monday和Sunday of each week生成最后4-8周的日期。

我试过这样做。

<?php
$dates_array = array();

$dates_array['-3 week monday'] = date('Y-m-d',strtotime("Last Monday - 3 week"));
$dates_array['-3 week sunday'] = date('Y-m-d',strtotime("Last Sunday - 3 week"));

$dates_array['-2 week monday'] = date('Y-m-d',strtotime("Last Monday - 2 week"));
$dates_array['-2 week sunday'] = date('Y-m-d',strtotime("Last Sunday - 2 week"));

$dates_array['last monday'] = date('Y-m-d',strtotime("Last Monday"));
$dates_array['last sunday'] = date('Y-m-d',strtotime("Last Sunday"));

$dates_array['this monday'] = date('Y-m-d',strtotime("Monday"));
$dates_array['this sunday'] = date('Y-m-d',strtotime("Sunday"));

print_r($dates_array);

产出：

Array
(
    [-3 week monday] => 2016-05-16
    [-4 week sunday] => 2016-05-15
    [-2 week monday] => 2016-05-30
    [-2 week sunday] => 2016-05-29
    [-1 week monday] => 2016-06-06
    [-1 week sunday] => 2016-06-05
    [last monday] => 2016-06-06
    [last sunday] => 2016-06-12
    [this monday] => 2016-06-13
    [this sunday] => 2016-06-19
)

我得到的产出对于本周和上周都是正确的，但在上周之前，一切都是一团糟，这是为什么？

我甚至试过这样做。

<?php
$dates_array = array();

$dates_array['-3 week monday'] = date('Y-m-d',strtotime("Monday", strtotime('-3 week')));
$dates_array['-3 week sunday'] = date('Y-m-d',strtotime("Sunday", strtotime('-3 week')));

$dates_array['-2 week monday'] = date('Y-m-d',strtotime("Monday", strtotime('-2 week')));
$dates_array['-2 week sunday'] = date('Y-m-d',strtotime("Sunday", strtotime('-2 week')));

$dates_array['last monday'] = date('Y-m-d',strtotime("Monday", strtotime('-1 week')));
$dates_array['last sunday'] = date('Y-m-d',strtotime("Sunday", strtotime('-1 week')));

$dates_array['this monday'] = date('Y-m-d',strtotime("Monday"));
$dates_array['this sunday'] = date('Y-m-d',strtotime("Sunday"));

print_r($dates_array);

产出：

Array
(
    [-3 week monday] => 2016-05-30
    [-3 week sunday] => 2016-05-29
    [-2 week monday] => 2016-06-06
    [-2 week sunday] => 2016-06-05
    [last monday] => 2016-06-13
    [last sunday] => 2016-06-12
    [this monday] => 2016-06-20
    [this sunday] => 2016-06-19
)

在上面的例子中，输出日期也很奇怪。

那么，使用PHP获取Monday和Sunday of each week最后4-8周日期的最佳方法是什么？

使用: PHP版本5.3.3

最新情况：

我设法得到了jeroen建议的正确日期，但是使用了相同的日期函数，如下所示

<?php

$dates_array = array();

$dates_array['-4 week monday'] = date('Y-m-d',strtotime("Monday", strtotime('this week -4 week')));
$dates_array['-4 week sunday'] = date('Y-m-d',strtotime("Sunday", strtotime('this week -4 week')));

$dates_array['-3 week monday'] = date('Y-m-d',strtotime("Monday", strtotime('this week -3 week')));
$dates_array['-3 week sunday'] = date('Y-m-d',strtotime("Sunday", strtotime('this week -3 week')));

$dates_array['-2 week monday'] = date('Y-m-d',strtotime("Monday", strtotime('this week -2 week')));
$dates_array['-2 week sunday'] = date('Y-m-d',strtotime("Sunday", strtotime('this week -2 week')));

$dates_array['last monday'] = date('Y-m-d',strtotime("Monday", strtotime('last week')));
$dates_array['last sunday'] = date('Y-m-d',strtotime("Sunday", strtotime('last week')));

$dates_array['this monday'] = date('Y-m-d',strtotime("Monday", strtotime('this week')));
$dates_array['this sunday'] = date('Y-m-d',strtotime("Sunday", strtotime('this week')));

print_r($dates_array);

产出：

Array
(
    [-4 week monday] => 2016-05-16
    [-4 week sunday] => 2016-05-22
    [-3 week monday] => 2016-05-23
    [-3 week sunday] => 2016-05-29
    [-2 week monday] => 2016-05-30
    [-2 week sunday] => 2016-06-05
    [last monday] => 2016-06-06
    [last sunday] => 2016-06-12
    [this monday] => 2016-06-13
    [this sunday] => 2016-06-19
)

Answer 1

使用时间戳和日期函数：

<?php
$timestamp = strtotime('20160604');

$day_of_the_week = date('N', $timestamp); // N returns mon-sun as digits 1 - 7. 

$sunday_ts = $timestamp + ( 7 - $day_of_the_week) * 24 * 60 * 60;
$monday_ts = $timestamp - ( $day_of_the_week - 1) * 24 * 60 * 60;

$dates = array();
for($i = 1; $i < 5; $i++) {
    $dates_key = '-' . $i . ' Week';
    $dates[$dates_key] = array(
        'Monday' => date('Y m d', $monday_ts - $i * 7 * 24 * 60 * 60),
        'Sunday' => date('Y m d', $sunday_ts - $i * 7 * 24 * 60 * 60)
        );
}

printf("Given date %s falls on a %s.\n", date('Y m d', $timestamp), date('l', $timestamp));
var_export($dates);

输出：

Given date 2016 06 04 falls on a Saturday.
array (
  '-1 Week' => 
  array (
    'Monday' => '2016 05 23',
    'Sunday' => '2016 05 29',
  ),
  '-2 Week' => 
  array (
    'Monday' => '2016 05 16',
    'Sunday' => '2016 05 22',
  ),
  '-3 Week' => 
  array (
    'Monday' => '2016 05 09',
    'Sunday' => '2016 05 15',
  ),
  '-4 Week' => 
  array (
    'Monday' => '2016 05 02',
    'Sunday' => '2016 05 08',
  ),
)

Answer 2

尝试以下方法，减少今天的倍数为7

    // This Week
    echo date("d-m-Y", strtotime("this Monday"))."<br>";
    echo date("d-m-Y", strtotime("this Sunday"))."<br>";

    // Last Week
    echo date("d-m-Y", strtotime("this Monday -7 day"))."<br>";
    echo date("d-m-Y", strtotime("this Sunday -7 day"))."<br>";

    // -2 Week
    echo date("d-m-Y", strtotime("this Monday -14 day"))."<br>";
    echo date("d-m-Y", strtotime("this Sunday -14 day"))."<br>";

    // -3 Week
    echo date("d-m-Y", strtotime("this Monday -21 day"))."<br>";
    echo date("d-m-Y", strtotime("this Sunday -21 day"))."<br>";

    // -4 Week
    echo date("d-m-Y", strtotime("this Monday -28 day"))."<br>";
    echo date("d-m-Y", strtotime("this Sunday -28 day"))."<br>";

    // -5 Week
    echo date("d-m-Y", strtotime("this Monday -35 day"))."<br>";
    echo date("d-m-Y", strtotime("this Sunday -35 day"))."<br>";

    // -6 Week
    echo date("d-m-Y", strtotime("this Monday -42 day"))."<br>";
    echo date("d-m-Y", strtotime("this Sunday -42 day"))."<br>";

    // -7 Week
    echo date("d-m-Y", strtotime("this Monday -49 day"))."<br>";
    echo date("d-m-Y", strtotime("this Sunday -49 day"))."<br>";

Answer 3

与其用周减去天数，不如使用当前日期的天数，如下所示。

 <?php
    date('Y-m-d',strtotime("Monday"));
    echo date('Y-m-d',strtotime('last monday  days'));
    echo date('Y-m-d',strtotime('last monday -7 days'));
    echo date('Y-m-d',strtotime('last monday -14 days'));
    echo date('Y-m-d',strtotime('last monday -21 days'));
    echo date('Y-m-d',strtotime('last monday -28 days'));
    ?>