php array in reverse order

print_r(krsort($arr));

var_dump($arr);

1array(3) {
[2]=>
string(3) "789"
[1]=>
string(3) "456"
[0]=>
string(3) "123"
}

ksort($arr);
var_dump($arr);

array(3) {
[0]=>
string(3) "123"
[1]=>
string(3) "456"
[2]=>
string(3) "789"
}