Basic UIPickerView Template

I am using extensions here just so you can see which functions belong to which protocols.

 
class ViewController: UIViewController {

    @IBOutlet weak var picker: UIPickerView!
    
    var data: [String] = ["Row 1", "Row 2", "Row 3"]
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        picker.dataSource = self
        picker.delegate = self
    }
}

extension ViewController: UIPickerViewDataSource {
    // Like number of columns
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 1
    }

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

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

(Swift 3)