排序字符串数组取决于之后的最后一次出现。？

Question

I have an array containing a list of filenames that I want to sort by extension. Folders first then files sorted by extension :

Consider the code below:

    $arr = array("noext","world.b","hello.a","test.z","lol.f");

Is there anyway how can I sort the array above depending on the extension to get something like the following :

    noext
    hello.a
    world.b
    lol.f
    test.z

I know I could use something like usort with a comparing function. But I have no idea how can I do it.

Any help would be highly appreciated.

Answer 1

You can indeed use usort:

<?php
$arr = array("noext","world.b","hello.a","test.z","lol.f");
usort($arr, function($s1, $s2) {
  $ext1 = pathinfo($s1, PATHINFO_EXTENSION);
  $ext2 = pathinfo($s2, PATHINFO_EXTENSION);
  return strcmp($ext1, $ext2);
});