从PHP 7.4开始，你可以使用arrow函数:

usort(
    $inventory, 
    fn(array $a, array $b): int => $b['price'] <=> $a['price']
);

代码(演示):

$inventory = [
    ['type' => 'fruit', 'price' => 3.50],
    ['type' => 'milk',  'price' => 2.90],
    ['type' => 'pork',  'price' => 5.43],
];

usort(
    $inventory, 
    fn(array $a, array $b): int => $b['price'] <=> $a['price']
);

print_r($inventory);

(浓缩)输出:

Array
(
    [0] => Array ([type] => pork,  [price] => 5.43)
    [1] => Array ([type] => fruit, [price] => 3.5)
    [2] => Array ([type] => milk,  [price] => 2.9)
)

试试这个:

asort($array_to_sort, SORT_NUMERIC);

参考如下: http://php.net/manual/en/function.asort.php

在这里查看各种排序标志: http://www.php.net/manual/en/function.sort.php

因为数组元素本身就是带有字符串键的数组，所以最好定义一个自定义比较函数。做起来又快又简单。试试这个:

function invenDescSort($item1,$item2)
{
    if ($item1['price'] == $item2['price']) return 0;
    return ($item1['price'] < $item2['price']) ? 1 : -1;
}
usort($inventory,'invenDescSort');
print_r($inventory);

产生以下结果:

Array
(
    [0] => Array
        (
            [type] => pork
            [price] => 5.43
        )

    [1] => Array
        (
            [type] => fruit
            [price] => 3.5
        )

    [2] => Array
        (
            [type] => milk
            [price] => 2.9
        )

)

您可以尝试定义自己的比较函数，然后使用usort。

$inventory = 
    array(array("type"=>"fruit", "price"=>3.50),
          array("type"=>"milk", "price"=>2.90),
          array("type"=>"pork", "price"=>5.43),
          );

function pricesort($a, $b) {
  $a = $a['price'];
  $b = $b['price'];
  if ($a == $b)
    return 0;
  return ($a > $b) ? -1 : 1;
}

usort($inventory, "pricesort");
// uksort($inventory, "pricesort");

print("first: ".$inventory[0]['type']."\n\n");
// for usort(): prints milk (item with lowest price)
// for uksort(): prints fruit (item with key 0 in the original $inventory)

// foreach prints the same for usort and uksort.
foreach($inventory as $i){
  print($i['type'].": ".$i['price']."\n");
}

输出:

first: pork

pork: 5.43
fruit: 3.5
milk: 2.9

如果需要对不同大小写的字符串数组进行排序，这将把排序数组的值更改为小写。

$data = [
    [
        'name' => 'jack',
        'eyeColor' => 'green'
    ],
    [
        'name' => 'Amy',
        'eyeColor' => 'brown'
    ],
    [   
        'name' => 'Cody',
        'eyeColor' => 'blue'
    ] 
];
function toLowerCase($a) { return strtolower($a); }
$sortArray = array_map("toLowerCase",array_column($data, 'name'));
array_multisort($sortArray, SORT_ASC, $data);