Un-naturally sort array by its numeric keys

I'm trying to sort an array by its numeric keys as if they were not numbers -- I don't want natural sorting.

$arr = [
    '1000' => 'DUMMY',
    '1001' => 'TEST',
    '100001' => 'DUMMY1',
    '100002' => 'DUMMY3',
    '100004' => 'DUMMY4',
    '100100' => 'test1',
    '100102' => 'DUMMY123'
];

After sorting, the result should be:

[
    '1000' => 'DUMMY',
    '100001' => 'DUMMY1',
    '100002' => 'DUMMY3',
    '100004' => 'DUMMY4',
    '1001' => 'TEST',
    '100100' => 'test1',
    '100102' => 'DUMMY开发者_运维百科123'
]

Because your array keys are "big-endian", you can explicitly sort the keys as strings (overriding the default behavior of `sort() to sort numeric values numerically). (Demo)

ksort($arr, SORT_STRING);

I'm not really sure understand what you want.
But i guess it's something like that:

this sort the array

1st : by the first 4 digits of the key
2nd : by the last 2 digits if they're present


$arr = array(
    '100102'  => 'DUMMY123',
    '100100'  => 'test1',
    '1000'    => 'DUMMY',
    '100004'  => 'DUMMY4',
    '100001'  => 'DUMMY1',
    '100002'  => 'DUMMY3',
    '1001'    => 'TEST',
);

function mysort($a, $b) {
    preg_match('/^(\d{4})(\d\d)?$/', $a, $ma);
    preg_match('/^(\d{4})(\d\d)?$/', $b, $mb);

    if ($ma[1] == $mb[1]) {
        if (!isset($ma[2])) $ma[2] = '';
        if (!isset($mb[2])) $mb[2] = '';
        return strcmp($ma[2], $mb[2]);
    }
    return strcmp($ma[1], $mb[1]);
}
uksort($arr, 'mysort');
print_r($arr);

Output:

Array
(
    [1000] => DUMMY
    [100001] => DUMMY1
    [100002] => DUMMY3
    [100004] => DUMMY4
    [1001] => TEST
    [100100] => test1
    [100102] => DUMMY123
)

asort() should do the trick no matter how many extra 2-character subcategories you add. With the SORT_STRING flag the category doesn't even have to be a string.

$arr =('100001'=>'DUMMY1',
       '1000'=>'DUMMY',
       '1001'=>'TEST',
       '100002'=>'DUMMY3',
       '100004'=>'DUMMY4',
       '100102'=>'DUMMY123',
       '100100'=>'test1');

asort($arr, SORT_STRING);

Should result in

$arr =('1000'=>'DUMMY',
       '100001'=>'DUMMY1',
       '100002'=>'DUMMY3',
       '100004'=>'DUMMY4',
       '1001'=>'TEST',
       '100100'=>'test1',
       '100102'=>'DUMMY123');