Sort multidimensional array by multiple keys

Question

I\'m trying to sort a multidimensional array by multiple keys, and I have no idea where to start. I looked at uasort, but wasn\'t quite sure how to write a function for what

Answer 1

You need array_multisort

$mylist = array(
    array('ID' => 1, 'title' => 'Boring Meeting', 'event_type' => 'meeting'),
    array('ID' => 2, 'title' => 'Find My Stapler', 'event_type' => 'meeting'),
    array('ID' => 3, 'title' => 'Mario Party', 'event_type' => 'party'),
    array('ID' => 4, 'title' => 'Duct Tape Party', 'event_type' => 'party')
);

# get a list of sort columns and their data to pass to array_multisort
$sort = array();
foreach($mylist as $k=>$v) {
    $sort['title'][$k] = $v['title'];
    $sort['event_type'][$k] = $v['event_type'];
}
# sort by event_type desc and then title asc
array_multisort($sort['event_type'], SORT_DESC, $sort['title'], SORT_ASC,$mylist);

As of PHP 5.5.0:

array_multisort(array_column($mylist, 'event_type'), SORT_DESC,
                array_column($mylist, 'title'),      SORT_ASC,
                $mylist);

$mylist is now:

array (
  0 => 
  array (
    'ID' => 4,
    'title' => 'Duct Tape Party',
    'event_type' => 'party',
  ),
  1 => 
  array (
    'ID' => 3,
    'title' => 'Mario Party',
    'event_type' => 'party',
  ),
  2 => 
  array (
    'ID' => 1,
    'title' => 'Boring Meeting',
    'event_type' => 'meeting',
  ),
  3 => 
  array (
    'ID' => 2,
    'title' => 'Find My Stapler',
    'event_type' => 'meeting',
  ),
)