segue.swift

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    performSegueWithIdentifier(“mySegueName”, sender: "hello!")
}

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if let vc = segue.destinationViewController as? DestVC {
        vc.dataFromAnotherVC as? String
    }
}