CI session not working properly

[eluser]manash007[/eluser]
From where i am writing in the session:

Code:

if($query->num_rows()){
$user = $query->result();//*************************
$this->session->set_userdata(’user’,$user);//*********************
return true;
}else{
$this->validation->set_message(’checklogin’,’User Name and Password do not match’);
return false;
}

where i am trying to read session data:
<?php
$userdata1 = $this->session->userdata('user');
$userdata = $userdata1[0];

var_dump($userdata);

?>