Answers for "ksort a specific value in an array"

php sort array by key

$weight = [
    'Pete' => 75, 
    'Benjamin' => 89,
    'Jonathan' => 101
  ];  	
  ksort($weight);

php sort array of array by key

$inventory = [
	['price' => 10.99, 'product' => 'foo 1'],
    ['price' => 5.99, 'product' => 'foo 2'],
  	['price' => 100, 'product' => 'foo 3'],
  
];

$price = array_column($inventory, 'price');

array_multisort($price, SORT_DESC, $inventory);