Array sort

Before sort

Array
(
    [1] => a
    [2] => z
    [3] => U
    [4] => x
    [5] => c
    [6] => s
    [7] => 5
    [8] => N
    [9] => 7
)

After sort

Array
(
    [0] => 5
    [1] => 7
    [2] => N
    [3] => U
    [4] => a
    [5] => c
    [6] => s
    [7] => x
    [8] => z
)