Sort the first and second level of a 2d array by numeric keys in DESC order

How can I sort inner array keys in DESC order?

I can sort 11, 12 in DESC order with arsort() but inner array remains same. I tried array_multisort(), usort() and others but without luck.

$array = [
    11 => [
        4 => 'apr11timetable.php',
        8 => 'aug11timetable.php',
        6 => 'jun11timetable.php',
        11 => 'nov11timetable.php',
        10 => 'oct11timetable.php'
    ],
    12 => [
        4 => 'apr12timetable.php',
        8 => 'aug12timetable.php',
        2 => 'feb12timetable.php',
        6 => 'jun12timetable.php',
        10 => 'oct12timetable.php'
    ]
];

You can try with ksort. Arsort will not sort your array properly.

<pre>
<?php
$array = Array(
    11 => Array(
        4 => 'apr11timetable.php',
        8 => 'aug11timetable.php',
        6 => 'jun11timetable.php',
        11 => 'nov11timetable.php',
        10 => 'oct11timetable.php'
    ),
    12 => Array(
        4 => 'apr12timetable.php',
        8 => 'aug12timetable.php',
        2 => 'feb12timetable.php',
        6 => 'jun12timetable.php',
        10 => 'oct12timetable.php'
    )
);

krsort($array, SORT_NUMERIC);

foreach ($array as &$arr) {    
    krsort($arr, SORT_NUMERIC);
}

print_r($array);
?>
</pre>