PHP double sort array based on substring - php

Question

I am building a custom switch manager for work, my current issue is more an aesthetic one but I think it is a good learning experience. I have posted the array below for clarity:
Array
(
[1] => FastEthernet0/1
[10] => FastEthernet0/10
[11] => FastEthernet0/11
[12] => FastEthernet0/12
[13] => FastEthernet0/13
[14] => FastEthernet0/14
[15] => FastEthernet0/15
[16] => FastEthernet0/16
[17] => FastEthernet0/17
[18] => FastEthernet0/18
[19] => FastEthernet0/19
[2] => FastEthernet0/2
[20] => FastEthernet0/20
[21] => FastEthernet0/21
[22] => FastEthernet0/22
[23] => FastEthernet0/23
[24] => FastEthernet0/24
[3] => FastEthernet0/3
[4] => FastEthernet0/4
[5] => FastEthernet0/5
[6] => FastEthernet0/6
[7] => FastEthernet0/7
[8] => FastEthernet0/8
[9] => FastEthernet0/9
[25] => Null0
)
On our bigger switches I am using asort($arr); to get GigabitEthernet1/1 to come before 2/1, etc...
My goal is to sort on the interface number (part after '/') so that 1/8 comes before 1/10.
Could someone point me in the right direction, I want to work for the results but I am not familiar enough with PHP to know exactly where to go.
Notes: On out larger multi-module switches the IDs are not in order so a sort on $arr[key] won't work.

Answer 1

You can use the flag while using asort(), like below.
asort($arr, SORT_NATURAL | SORT_FLAG_CASE);print_r($arr);
It will print/sort the data as yo need.

Answer 2

The SORT_NATURAL and SORT_FLAG_CASE requires v5.4+.
If you're using an older version of PHP, you could do it with uasort and a custom comparison callback function.
$interfaces = array(...);
$ifmaj = array();
$ifmin = array();
$if_cmp = function ($a, $b) {
list($amaj,$amin) = split('/',$a);
list($bmaj,$bmin) = split('/',$b);
$maj = strcmp($amaj,$bmaj);
if ($maj!=0) return $maj;
//Assuming right side is an int
return $amin-$bmin;
};
uasort($interfaces, $if_cmp);