class SemanaViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, UIPickerViewDataSource, UIPickerViewDelegate {

    let letters = ["A","B","C","D","F","G","H"]

    @IBOutlet weak var pickerView: UIPickerView!

    override func viewDidLoad() {
        super.viewDidLoad()
        self.tableView.delegate = self
        self.tableView.dataSource = self
        self.pickerView.dataSource = self
        self.pickerView.delegate = self
        ....
    }
....
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 1
    }

    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return letters.count
    }


    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        return letters[row]
    }