Question

In PHP, how might one sort an array by the last couple of characters of its values? Take, for example, the following array:

$donuts[0] = "Chocolate 02";
$donuts[1] = "Jelly 16";
$donuts[2] = "Glazed 01";
$donuts[3] = "Frosted 12";

After the sort, the array would look like this (note the order based on the last two characters of each value… also note the rewritten indexes):

$donuts[0] = "Glazed 01";
$donuts[1] = "Chocolate 02";
$donuts[2] = "Frosted 12";
$donuts[3] = "Jelly 16";

I can’t seem to find a built-in function that can do this and have been racking my brain for the simplest and most efficient way to get this accomplished. Help! And thanks!

Answer 1

This should do the trick:

header('Content-Type: Text/Plain');
$donuts[0] = "Chocolate 02";
$donuts[1] = "Jelly 16";
$donuts[2] = "Glazed 01";
$donuts[3] = "Frosted 12";

print_r($donuts);

usort($donuts, function ($a, $b){
    return substr($b, -2) - substr($a, -2);
});

print_r($donuts);

NOTE

1. To convert from highest to smallest:

   return substr($b, -2) - substr($a, -2);
   

2. This answer make an assumption that the last 2 characters is to be used.

UPDATE

To make it work on PHP version 5.2, change the return part to:

return substr($b, strlen($b) - 2) - substr($a, strlen($a) - 2);