sort multidimensional array php by key

1function sortByAge($a, $b) {
2    return $a['age'] > $b['age'];
3}
4$people=[
5    ["age"=>54,"first_name"=>"Bob","last_name"=>"Dillion"],
6    ["age"=>22,"first_name"=>"Sarah","last_name"=>"Harvard"],
7    ["age"=>31,"first_name"=>"Chuck","last_name"=>"Bartowski"]
8];
9
10usort($people, 'sortByAge'); //$people is now sorted by age (ascending)

1array_multisort(array_map(function($element) {
2      return $element['order'];
3  }, $array), SORT_ASC, $array);
4
5print_r($array);

1		$keys = array_column($array, 'Price');
2
3		array_multisort($keys, SORT_ASC, $array);
4	
5		print_r($array);

1$inventory = array(
2   array("type"=>"Fruit", "price"=>3.50),
3   array("type"=>"milk", "price"=>2.90),
4   array("type"=>"Pork", "price"=>5.43),
5);
6
7$prices = array_column($inventory, 'price');
8$inventory_prices = array_multisort($prices, SORT_DESC, $inventory);
9
10$types = array_map(strtolower, array_column($inventory, 'type'));
11$inventory_types = array_multisort($types, SORT_ASC, $inventory);

1usort($myArray, function($a, $b) {
2    return $a['order'] <=> $b['order'];
3});

1$people= array(
2    array("age"=>54,"first_name"=>"bob","last_name"=>"Dillion"),
3    array("age"=>22,"first_name"=>"darah","last_name"=>"Harvard"),
4    array("age"=>31,"first_name"=>"ahuck","last_name"=>"Bartowski"),
5);
6
7echo '<PRE>';
8print_r($people);
9
10
11$keys = array_column($people, 'first_name');
12print_r($keys);
13
14array_multisort($keys, SORT_ASC, $people);
15
16print_r($people);