Description:
------------
在数字和字母混合的键值数组中 数字key被重新排列了
use array_slice
array keys for number and string
the result is err!

Reproduce code:
---------------
$thisArray=array(1=>0,2=>31,"a9"=>1,"0"=>3,"abc"=>20);
print_r($thisArray);
$a2=array_slice($thisArray,0,100);
print_r($a2);

Expected result:
----------------
Array
(
    [1] => 0
    [2] => 31
    [a9] => 1
    [0] => 3
    [abc] => 20
)
Array
(
    [1] => 0
    [2] => 31
    [a9] => 1
    [0] => 3
    [abc] => 20
)

Actual result:
--------------
Array
(
    [1] => 0
    [2] => 31
    [a9] => 1
    [0] => 3
    [abc] => 20
)
Array
(
    [0] => 0
    [1] => 31
    [a9] => 1
    [2] => 3
    [abc] => 20
)