Naming Convention in imports - use \class vs use class

Question

I found that, "Magento 2, At its core is PSR-4 compliant".

Then I got into this: https://www.php-fig.org/psr/psr-4/

and the table at the bottom:

FULLY QUALIFIED CLASS NAME -> \Acme\Log\Writer\File_Writer

So I see from the most of Magento2 Code cases, that it uses:

use Magento\Catalog\Helper\Data;

shouldn't it be like :

use \Magento\Catalog\Helper\Data;

when it points to a class ?

and then when it comes to Constructors in Magento2 I can clearly see that this kind of syntax is used:

    \Magento\Catalog\Helper\Data;

Is used

mb I'm missing some core fundamentals but I'm curious about it :D

Answer 1

• \ (backslash) represents the global namespace (root scope) in the starting of a namespace. check: What does a \ (backslash) do in PHP (5.3+)?
• use is a way of using a class, function, const in another class. All use namespaces are not processed relative to the current namespace but to global namespace, so adding a preceeding \ is unecessary and invalid. check: Using namespaces: Aliasing/Importing