What are some popular PHP template systems available for use in web development?

When developing web applications using PHP, it is common practice to use template systems to separate the presentation layer from the business logic. Popular PHP template systems include Smarty, Twig, Blade, and Plates. These template engines offer features such as template inheritance, variable substitution, loops, and conditionals, making it easier to create and manage the frontend of web applications.

// Example using Twig template engine
require_once 'vendor/autoload.php';

$loader = new Twig_Loader_Filesystem('templates');
$twig = new Twig_Environment($loader);

echo $twig->render('index.html', ['name' => 'John Doe']);