Updating a session array

Hello Igniters,

Sorry to bring up such an old topic, I'm having the exact same problem.

I was wondering how to handle multi-level session variables using CodeIgniter?

For now, I'm using:

PHP Code:

// Initialization
session()->push('app1', ['subA' => []]);
// Creating a variable into app1/subA 
session('app1')['subA']['var01'] = "Such text"; 


But if I want to check elsewhere in the code if the var01 exists recursively, how do I achieve this?

PHP Code:

// For now, I use:
if (isset(session('app1') && isset(session('app1')['subA']) && isset(session('app1')['subA']['var01'])) 

// I would expect something like :
session('app1')->has('subA.var01');
// or
session()->has('app1.subA.var01'); 


Same problem if I want to delete subA but not others variables into app1 ?

PHP Code:

// For now, I use:
unset($_SESSION['app1']['subA']);

// I would expect something like :
session('app1')->remove('subA');
// or
session()->remove('app1.subA'); 


So I asked myself: am I doing things wrong?
I mean: what are the best practices for handling session subvariables?