我如何在PHP中按日期排序数组

Question

I have this array and i want to sort it in ascending order by date. I tried various answers from this site but none of them is working right. So how can I do this?

Array
(
    [0] => 09/01/2017
    [1] => 08/01/2017
    [2] => 07/01/2017
    [3] => 06/01/2017
    [4] => 05/01/2017
    [5] => 04/01/2017
    [6] => 03/01/2017
    [7] => 02/01/2017
    [8] => 01/01/2017
    [9] => 12/12/2016
    [10] => 11/12/2016
    [11] => 10/12/2016
    [12] => 09/12/2016
    [13] => 25/12/2016
    [14] => 24/12/2016
    [15] => 23/12/2016
    [16] => 26/12/2016
    [17] => 28/12/2016
    [18] => 30/12/2016
    [19] => 29/12/2016
    [20] => 22/12/2016
    [21] => 27/12/2016
    [22] => 15/12/2016
    [23] => 16/12/2016
    [24] => 14/12/2016
    [25] => 13/12/2016
    [26] => 17/12/2016
    [27] => 18/12/2016
    [28] => 20/12/2016
    [29] => 19/12/2016
    [30] => 21/12/2016
)

I am using PHP. This is what i tried so far. This function doesn't sort as mentioned in all other questions.

$data = array listed above;
function cmp($a, $b)
{
    if (strtotime($a) == strtotime($b))
    {
        return 0;
    }
    return (strtotime($a) < strtotime($b)) ? -1 : 1;
}

uasort($data, "cmp");

Answer 1

For you string is dd/mm/yy type, cannot directly used by strtotime or date_create. You can use DataTime to create the datetime, then use the datetime compare operators.

usort($array, function($a, $b){return DateTime::createFromFormat('d/m/Y', $a) > DateTime::createFromFormat('d/m/Y', $b);});