The Use Command and Namespaces in OOP in PHP

Let us have the following class Data:

/core/admin/data.php<?php
  namespace \Core\Admin;
  
  class Data
  {
    public function __construct($num)
    {
      
    }
  }
?>

Let there also be a class Page that creates objects of the Data class inside itself:

/users/page.php<?php
  namespace Users;
  
  class Page
  {
    public function __construct()
    {
      $data1 = new \Core\Admin\Data('1');
      $data2 = new \Core\Admin\Data('2');
    }
  }
?>

As you can see, both of our classes are in completely different namespaces, so calls to the Data class cannot be simplified, similar to how we did it in the previous lesson. However, these calls are very long and inconvenient, because in each call to the Data class, its long namespace has to be specified.

To solve this problem, there is a special command use. Using this command, it is enough to connect the class by its full name once, and after that it will be possible to refer to this class simply by the class name. See the example:

/users/page.php<?php
  namespace Users;
  use \Core\Admin\Data; // connect the class
  
  class Page extends Controller
  {
    public function __construct()
    {
      $data1 = new Data('1'); // call simply by name
      $data2 = new Data('2'); // call simply by name
    }
  }
?>

php<?php
  namespace Project;
  
  class Test
  {
    public function __construct()
    {
      // Create 3 objects of the same class:
      $data1  = new \Core\Users\Data('user1');
      $data2  = new \Core\Users\Data('user3');
      $data3  = new \Core\Users\Data('user3');
    }
  }
?>

php<?php
  namespace Core\Admin;
  
  class Controller
  {
    
  }
?>

php<?php
  namespace Users;
  
  class Page extends \Core\Admin\Controller
  {
    
  }
?>