php sub list
function sortByAge($a, $b) { return $a['age'] > $b['age']; } $people=[ ["age"=>54,"first_name"=>"Bob","last_name"=>"Dillion"], ["age"=>22,"first_name"=>"Sarah","last_name"=>"Harvard"], ["age"=>31,"first_name"=>"Chuck","last_name"=>"Bartowski"] ]; usort($people, 'sortByAge'); //$people is now sorted by age (ascending)