sort array by key value in php

1$inventory = array(
2
3   array("type"=>"fruit", "price"=>3.50),
4   array("type"=>"milk", "price"=>2.90),
5   array("type"=>"pork", "price"=>5.43),
6
7);
8$price = array_column($inventory, 'price');
9array_multisort($price, SORT_DESC, $inventory);

1  $weight = [
2    'Pete' => 75, 
3    'Benjamin' => 89,
4    'Jonathan' => 101
5  ];  	
6  ksort($weight);

1
2usort($array, function ($a, $b) {
3  return ($a['specific_key'] < $b['specific_key']) ? -1 : 1;
4});
5

1$inventory = [
2	['price' => 10.99, 'product' => 'foo 1'],
3    ['price' => 5.99, 'product' => 'foo 2'],
4  	['price' => 100, 'product' => 'foo 3'],
5  
6];
7
8$price = array_column($inventory, 'price');
9
10array_multisort($price, SORT_DESC, $inventory);

1To PHP sort array by key, you should use: 
2	ksort() (for ascending order) or krsort() (for descending order). 
3      
4To PHP sort array by value, you will need functions:
5	asort() and arsort() (for ascending and descending orders).

1    function cmp($a, $b)
2    {
3        return strcmp($a->display_name, $b->display_name);
4    }
5
6    usort($blogusers, "cmp");
7
8    foreach ($blogusers as $bloguser)
9    {
10        ...