How to store variable in session codeigniter

Question

I would like to store the variable in the session currently i am tryin like this but not working.

In Controller

Answer 1

Codeigniter

set in session

$newdata = array(
                   'username'  => 'johndoe',
                   'email'     => 'johndoe@some-site.com',
                   'logged_in' => TRUE
               );

$this->session->set_userdata($newdata);

retrieve from session

$this->session->userdata('username');