Basically I could upload files based on a project. Whenever I create a project, a new directory is created with the directory name as the project_name e.g. this is a test -> this-is-a-test. But my problem is I couldn't delete a file in a directory.

function delete_image($id)
{
    $this->load->model(array('work_model', 'project_model'));
    $result = $this->work_model->get_work($id);
    $result = $this->project_model->get_project($result->project_id);
    $dir = str_replace(" ", "-", $result->project_name);
    $result = $this->work_model->delete($id);
    if (isset($result)){
        unlink('./uploads/' . $dir . '/' . $result->full_path);  
    }
    redirect('admin/project/view_project/' . $result->project_id);
}

Need help on this thanks.