如何在foreach循环中获取唯一值

$numbers = array(1, 2, 3, 4, 3, 2, 1);

foreach (array_unique($numbers) as $number) {
    echo $number;
}

$student_scores = array(
    "Alice" => 85,
    "Bob" => 92,
    "Alice" => 90,
    "Charlie" => 88
);

$unique_names = array_keys($student_scores);
foreach ($unique_names as $name) {
    echo $name;
}

class Person {
    public $name;
    public $age;

    public function __construct($name, $age) {
        $this->name = $name;
        $this->age = $age;
    }
}

$people = array(
    new Person("Alice", 25),
    new Person("Bob", 30),
    new Person("Alice", 28),
    new Person("Charlie", 35)
);

$unique_names = array_column($people, "name");
foreach (array_unique($unique_names) as $name) {
    echo $name;
}