PHP 配列の高度な並べ替え: カスタム コンパレーターと匿名関数

class CustomComparator implements Comparable {
    public function compareTo($a, $b): int {
        if ($a == $b) {
            return 0;
        }
        return $a > $b ? 1 : -1;
    }
}

$comparator = function($a, $b) {
    if ($a == $b) {
        return 0;
    }
    return $a > $b ? 1 : -1;
};

$students = [
    ['name' => 'Alice', 'score' => 85],
    ['name' => 'Bob', 'score' => 90],
    ['name' => 'Carol', 'score' => 80],
];

$comparator = new CustomComparator();
usort($students, [$comparator, 'compareTo']);

usort($students, function($a, $b) {
    return $a['score'] <=> $b['score'];
});

[
    ['name' => 'Carol', 'score' => 80],
    ['name' => 'Alice', 'score' => 85],
    ['name' => 'Bob', 'score' => 90],
];