在PHP 7中对关联数组进行排序[重复]

Question

This question already has an answer here:

• How to sort an array of arrays in php? 2 answers

Given the following example:

$user1 = array('username' => 'test1', 'score' => 2000, 'someotherdata' => 1.0);
$user2 = array('username' => 'test2', 'score' => 4325, 'someotherdata' => 2.0);
$user3 = array('username' => 'test3', 'score' => 624534, 'someotherdata' => 3.0);
$user4 = array('username' => 'test4', 'score' => 564, 'someotherdata' => 1.4);
$user5 = array('username' => 'test5', 'score' => 34256, 'someotherdata' => 1.5);
$user6 = array('username' => 'test6', 'score' => 5476, 'someotherdata' => 1.8);

$arr = array($user1, $user2, $user3, $user4, $user5, $user6);

How would I be able to sort $arr by the field score nicely in PHP 7? I got a working bubblesort I made my own, but is there a way to use builtin PHP 7 features to do it nicely, as bubblesort is pretty expensive (I could do a Quicksort on my own, but before I do that I wanted to know if there is a better way).

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Answer 1

You can use usort

$user1 = array('username' => 'test1', 'score' => 2000, 'someotherdata' => 1.0);
$user2 = array('username' => 'test2', 'score' => 4325, 'someotherdata' => 2.0);
$user3 = array('username' => 'test3', 'score' => 624534, 'someotherdata' => 3.0);
$user4 = array('username' => 'test4', 'score' => 564, 'someotherdata' => 1.4);
$user5 = array('username' => 'test5', 'score' => 34256, 'someotherdata' => 1.5);
$user6 = array('username' => 'test6', 'score' => 5476, 'someotherdata' => 1.8);

$arr = array($user1, $user2, $user3, $user4, $user5, $user6);

usort($arr, function($a, $b){
    return $a['score'] - $b['score'];
});

echo "<pre>";
print_r( $arr );
echo "</pre>";

This will result to:

Array
(
    [0] => Array
        (
            [username] => test4
            [score] => 564
            [someotherdata] => 1.4
        )

    [1] => Array
        (
            [username] => test1
            [score] => 2000
            [someotherdata] => 1
        )

    [2] => Array
        (
            [username] => test2
            [score] => 4325
            [someotherdata] => 2
        )

    [3] => Array
        (
            [username] => test6
            [score] => 5476
            [someotherdata] => 1.8
        )

    [4] => Array
        (
            [username] => test5
            [score] => 34256
            [someotherdata] => 1.5
        )

    [5] => Array
        (
            [username] => test3
            [score] => 624534
            [someotherdata] => 3
        )

)

Doc: usort()