closure in php

closure.php

<?php
function grouped_data_sorter($key) {
  return function ($a, $b) use ($key) {
    return strnatcmp($a[0]->$key, $b[0]->$key);
  };
}

uasort($grouped_data, grouped_data_sorter('total_users'));

Wow. I had no idea PHP supports closures. Nice one.