Sort an array of alphabetic and numeric string-type elements ASC, but with numeric elements after alphabetic elements

I have an array of values which are either all-letters or all-numbers and need to sort them in an ascending fashion. Additionally, I want all-numeric values to be moved to the end of the array so that they occur after all of the non-numeric values.

$test = ["def", "yz", "abc", "jkl", "123", "789", "stu"];

If I run sort() on it I get:

Array
(
    [0] => 123
    [1] => 789
    [2] => abc
    [3] => def
    [4] => jkl
    [5] => stu
    [6] => yz
)

but I’d like to see:

Array
(
    [0] => abc
    [1] => def
    [2] => jkl
    [3] => stu
    [4] => yz
    [5] => 123
    [6] => 789
)

I tried array_reverse(), but that didn’t seem to change anything. I’m at a loss for how to get the numbers last, but in ascending order.

Answer

What you need is sort but with a custom comparison function (usort). The following code will get it done:

function myComparison($a, $b){
    if(is_numeric($a) && !is_numeric($b))
        return 1;
    else if(!is_numeric($a) && is_numeric($b))
        return -1;
    else
        return ($a < $b) ? -1 : 1;
} 
$test = array("def", "yz", "abc", "jkl", "123", "789", "stu");
usort ( $test , 'myComparison' );