How to sort by key within multidimensional array

Question

I made this fictional membership list. I'd like to maintain the order of the sub arrays (class year) while sorting by descending key within each sub array.

$pledges = array(
  'smith'     => "Joe Patterson",
  'jones'     => "Robert Nelson",
  'davis'     => "Jimmy Davis",
  'carpenter' => "Mike Carpenter");

$sophomores = array(
  'ford'      => "Kevin Ford",
  'gomez'     => "Pedro Gomez",
  'miller'    => "Jack Miller",
  'pullman'   => "Lucas Pullman");

$juniors = array(
  'bradford'  => "Nicholas Bradford",
  'daniels'   => "Robert Daniels",
  'soren'     => "Jon Soren",
  'cooper'    => "Harrison Cooper");

$seniors = array(
  'mcdonald'  => "Casey McDonald",
  'witten'    => "Tim Witten",
  'session'   => "Benjamin Sessions",
  'redding'   => "Jack Redding");

How do I do that? Thanks a bunch.

Answer 1

The PHP manual has a good example of what you're looking to do.

http://www.php.net/manual/en/function.ksort.php#98465

Answer 2

by using ksort function of PHP you can sort array key wise.

ksort($pledges);
array_reverse($pledges);
and like wise for others....

what you have posted is single dimension array and be aware that ksort will be only applicable to single dimension array.