Sort multidimensional array by multiple columns

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 I need.

I need to sort by the state, then event_type, then date_start.

My array looks like this:

[     ['ID' => 1, 'title' => 'Boring Meeting',  'date_start' => '2010-07-30', 'event_type' => 'meeting', 'state' => 'new-york'],     ['ID' => 2, 'title' => 'Find My Stapler', 'date_start' => '2010-07-22', 'event_type' => 'meeting', 'state' => 'new-york'],     ['ID' => 3, 'title' => 'Mario Party',     'date_start' => '2010-07-22', 'event_type' => 'party',   'state' => 'new-york'],     ['ID' => 4, 'title' => 'Duct Tape Party', 'date_start' => '2010-07-28', 'event_type' => 'party',   'state' => 'california'] ] 

My desired result is:

[     ['ID' => 4, 'title' => 'Duct Tape Party', 'date_start' => '2010-07-28', 'event_type' => 'party',   'state' => 'california']     ['ID' => 2, 'title' => 'Find My Stapler', 'date_start' => '2010-07-22', 'event_type' => 'meeting', 'state' => 'new-york'],     ['ID' => 1, 'title' => 'Boring Meeting',  'date_start' => '2010-07-30', 'event_type' => 'meeting', 'state' => 'new-york'],     ['ID' => 3, 'title' => 'Mario Party',     'date_start' => '2010-07-22', 'event_type' => 'party',   'state' => 'new-york'], ] 

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',   ), )