PHP 的新功能

class user {    private string $firstname;    private string $lastname;    public function __construct(string $firstname, string $lastname) {        $this->firstname = $firstname;        $this->lastname = $lastname;    }    // this property combines first and last name    public string $fullname {        get => $this->firstname . ' ' . $this->lastname;        set => [$this->firstname, $this->lastname] = explode(' ', $value, 2);    }}$user = new user('john', 'doe');echo $user->fullname; // output: john doe$user->fullname = 'jane smith'; // updates first and last namesecho $user->fullname; // output: jane smith

class bankaccount {    public private(set) float $balance; // public read, private write    public function __construct(float $initialbalance) {        $this->balance = $initialbalance; // allowed here    }    public function deposit(float $amount): void {        $this->balance += $amount; // allowed here    }}$account = new bankaccount(100.0);echo $account->balance; // output: 100$account->deposit(50.0); // adds 50 to the balanceecho $account->balance; // output: 150// the following line will cause an error:// $account->balance = 200.0;

$numbers = [1, 2, 3, 4, 5];// find the first even number$firsteven = array_find($numbers, fn($n) => $n % 2 === 0);echo $firsteven; // output: 2// check if any number is greater than 4$hasbignumber = array_any($numbers, fn($n) => $n > 4);var_dump($hasbignumber); // output: bool(true)// check if all numbers are positive$allpositive = array_all($numbers, fn($n) => $n > 0);var_dump($allpositive); // output: bool(true)

class logger {    public function log(string $message): void {        echo $message;    }}// create an object and call a method in one stepnew logger()->log('logging a message'); // output: logging a message

// php 8.4 (recommended):function process(?string $data = null) {    echo $data ?? 'no data provided';}

class ExpensiveResource {    public function __construct() {        // Simulate a time-consuming setup        sleep(2);    }    public function doWork(): void {        echo 'Working...';    }}// Use a lazy object to delay creation$initializer = fn() => new ExpensiveResource();$reflector = new ReflectionClass(ExpensiveResource::class);$resource = $reflector->newLazyProxy($initializer);// The object isn't created yet$resource->doWork(); // Now the object is created and "Working..." is printed