php - 跨年 DatePeriod 宽度 DateInterval P7D 不计新年周

Question

我正在尝试像这样使用 PHP DatePeriod 来创建一个年周数组:

$from = new DateTime('2014-09-16');
$to = new DateTime('2015-02-25');

$interval = new DateInterval('P7D'); // 7Days => 1 Week
$daterange = new DatePeriod($from, $interval, $to);

$yearweeks = array();
foreach($daterange as $date) {
    $yearweeks[$date->format('YW')] = 'W' . $date->format('W-Y');
}

结果很奇怪!新年的第一周不见了。我有前一年的第一周而不是这样:

Array
(
    ...
    [201451] => W51-2014
    [201452] => W52-2014
    [201401] => W01-2014 // WTF ? /!\ [201501] => W01-2015 expected ! /!\
    [201502] => W02-2015
    [201503] => W03-2015
    ...
)

是否有避免此类错误的技巧？

Answer 1

您需要使用 ISO 年份，格式为 'o':

$yearweeks[$date->format('oW')] = 'W' . $date->format('W-o');

来自PHP date docs :

o

ISO-8601 year number. This has the same value as Y, except that if the ISO week number (W) belongs to the previous or next year, that year is used instead. (added in PHP 5.1.0)

Examples: 1999 or 2003