PHP 数组函数 natcasesort()

<?php
   $array1 = array('click0.txt', 'click12.txt', 'click10.txt', 'click2.txt', 'click1.txt', 'click3.txt');
   $array2 = $array1;
   natcasesort($array2);
   echo " \n Natural order sorting (case-insensitive) \n";
   print_r($array2);
?>