php - 无法使用 PHP 对日期进行排序

Question

我有一个看起来像这样的 PHP 数组：

$dates = array();
$dates['01-07-2013'] = 'dummy data';
$dates['01-21-2013'] = 'dummy data';
$dates['01-28-2013'] = 'dummy data';
$dates['01-20-2012'] = 'dummy data';

使用ksort($dates)时，它们没有正确排序。有没有办法像这样对键进行排序？

我希望排序返回：

'01-30-2012',
'01-07-2013',
'01-21-2013',
'01-28-2013',

Answer 1

Those aren't dates, as far as PHP is concerned. They're strings, so it's applying standard string sorting rules to it.

You'll need to define a custom sort function for use with usort(), or convert those dates to a format that IS sortable as a string, e.g.

yyyy-mm-dd

Answer 2

$dates = array();
$dates[time()] = 'dummy data';

Converting to unix timestamp may help as it is just a number (integer) that can be sorted easily.

Answer 3

ksort默认排序类型为SORT_REGULAR

SORT_REGULAR - 正常比较项目（不要更改类型）

并且您的日期格式将在 PHP 中评估为通用字符串。

您需要对这些进行格式化，以便将它们作为字符串排序。

Answer 4

您可以使用 uksort，但在比较功能中如下所示：

function sort_func($date1, $date2){
    return strtotime(str_replace("-","/", $date1)) - strtotime(str_replace("-","/", $date2));
}

uksort($dates, "sort_func");