在 PHP 中对数组的数组进行排序

Question

Request your help on sorting an array of array in PHP as below, tried all these function ksort, usort, arsort, krsort nothing seem to be working, any help would be much appreciated.

Original Array

Array
(
    [serv1-DB] => Array
        (
            [2019-11-22] => 0
            [2019-11-23] => 0
            [2019-11-24] => 0
            [2019-11-25] => 1
            [2019-11-26] => 3
            [2019-11-27] => 3
            [2019-11-28] => 3
            [2019-11-29] => 3
        )

    [ser2-DB] => Array
        (
            [2019-11-25] => 0
            [2019-11-24] => 0
            [2019-11-22] => 0
            [2019-11-23] => 0
            [2019-11-26] => 3
            [2019-11-27] => 3
            [2019-11-28] => 3
            [2019-11-29] => 3
        )

Output Required

Array
(
    [serv1-DB] => Array
        (
            [2019-11-29] => 3
            [2019-11-28] => 3
            [2019-11-27] => 3
            [2019-11-26] => 3
            [2019-11-25] => 1
            [2019-11-24] => 0
            [2019-11-23] => 0
            [2019-11-22] => 0

        )

    [ser2-DB] => Array
        (
            [2019-11-29] => 3
            [2019-11-28] => 3
            [2019-11-27] => 3
            [2019-11-26] => 3
            [2019-11-25] => 0
            [2019-11-24] => 0
            [2019-11-23] => 0
            [2019-11-22] => 0

        )

Answer 1

You want to sort the sub arrays, so you need to loop over each of them (in write mode) and sort the keys in reverse order using krsort :

foreach ($array as &$subArray) {
  krsort($subArray);
}

Demo: https://3v4l.org/g8pBu

Answer 2

You have to sort reversely on the arrays like this:

// The arrays
$arrays = array(
    "serv1-DB" => array(
        "2019-11-22" => 0,
        "2019-11-23" => 0,
        "2019-11-24" => 0,
        "2019-11-25" => 1,
        "2019-11-26" => 3,
        "2019-11-27" => 3,
        "2019-11-28" => 3,
        "2019-11-29" => 3
    ),
    "ser2-DB" => array(
        "2019-11-25" => 0,
        "2019-11-24" => 0,
        "2019-11-22" => 0,
        "2019-11-23" => 0,
        "2019-11-26" => 3,
        "2019-11-27" => 3,
        "2019-11-28" => 3,
        "2019-11-29" => 3
    )
);

// The sorting part
foreach($arrays AS $k => $array) {
    krsort($array);
    $arrays[$k] = $array;
}