给定这个数组:

$inventory = array(

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

);

我想按价格排序$inventory的元素,以获得:

$inventory = array(

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

);

我该怎么做呢?


当前回答

这个函数是可重用的:

function usortarr(&$array, $key, $callback = 'strnatcasecmp') {
    uasort($array, function($a, $b) use($key, $callback) {
        return call_user_func($callback, $a[$key], $b[$key]);
    });
}

默认情况下,它在字符串值上工作得很好,但如果所有值都是数字,则必须为数字比较函数指定子回调函数。

其他回答

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);

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
        )

)

我是这样用的

<?php
$users = [
    [
        'username' => 'joe',
        'age' => 11
    ],
    [
        'username' => 'rakoto',
        'age' => 21
    ],
    [
        'username' => 'rabe',
        'age' => 17
    ],
    [
        'username' => 'fy',
        'age' => 19
    ],    
];


uasort($users, function ($item, $compare) {
    return $item['username'] >= $compare['username']; 
});

var_dump($users);

试试这个:

$prices = array_column($inventory, 'price');
array_multisort($prices, SORT_DESC, $inventory);
print_r($inventory);

完整的动态功能 我跳到这里进行关联数组排序,并在http://php.net/manual/en/function.sort.php上找到了这个惊人的函数。这个函数是非常动态的,用指定的键按升序和降序排序。

按特定键对数组排序的简单函数。维护索引关联

<?php

function array_sort($array, $on, $order=SORT_ASC)
{
    $new_array = array();
    $sortable_array = array();

    if (count($array) > 0) {
        foreach ($array as $k => $v) {
            if (is_array($v)) {
                foreach ($v as $k2 => $v2) {
                    if ($k2 == $on) {
                        $sortable_array[$k] = $v2;
                    }
                }
            } else {
                $sortable_array[$k] = $v;
            }
        }

        switch ($order) {
            case SORT_ASC:
                asort($sortable_array);
            break;
            case SORT_DESC:
                arsort($sortable_array);
            break;
        }

        foreach ($sortable_array as $k => $v) {
            $new_array[$k] = $array[$k];
        }
    }

    return $new_array;
}

$people = array(
    12345 => array(
        'id' => 12345,
        'first_name' => 'Joe',
        'surname' => 'Bloggs',
        'age' => 23,
        'sex' => 'm'
    ),
    12346 => array(
        'id' => 12346,
        'first_name' => 'Adam',
        'surname' => 'Smith',
        'age' => 18,
        'sex' => 'm'
    ),
    12347 => array(
        'id' => 12347,
        'first_name' => 'Amy',
        'surname' => 'Jones',
        'age' => 21,
        'sex' => 'f'
    )
);

print_r(array_sort($people, 'age', SORT_DESC)); // Sort by oldest first
print_r(array_sort($people, 'surname', SORT_ASC)); // Sort by surname