What are some recommended PHP frameworks for building web applications?

When building web applications using PHP, utilizing a framework can help streamline development, improve code organization, and provide built-in functionalities. Some recommended PHP frameworks for building web applications include Laravel, Symfony, CodeIgniter, and CakePHP.

// Example code snippet using Laravel framework
Route::get('/welcome', function () {
    return view('welcome');
});

// Example code snippet using Symfony framework
use Symfony\Component\HttpFoundation\Response;

$response = new Response(
    'Hello, Symfony!',
    Response::HTTP_OK,
    ['content-type' => 'text/html']
);

$response->send();

// Example code snippet using CodeIgniter framework
public function index()
{
    $this->load->view('welcome_message');
}

// Example code snippet using CakePHP framework
public function hello()
{
    $this->set('message', 'Hello, CakePHP!');
}