UITextField возвращает число в функцию

У меня тусклый один UITextField на моем раскадровке, Как я могу вернуть номер в мое удовольствие. моя радость:

func translet(number:Double,from:String,to:String) -> Double

Полный код:

import UIKit

class ViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {

    @IBOutlet weak var unitTypePicker: UIPickerView!
    @IBOutlet weak var unitFromPicker: UIPickerView!
    @IBOutlet weak var unitToPicker: UIPickerView!

    @IBOutlet weak var unitTypeLabel: UILabel!
    @IBOutlet weak var unitFromLabel: UILabel!
    @IBOutlet weak var unitToLabel: UILabel!
    @IBOutlet weak var TrabsletCacl: UILabel!
    @IBOutlet weak var textinput: UITextField!


    @IBAction func unitTypeBTN(sender: AnyObject) {
        unitTypePicker.hidden = false
        unitFromPicker.hidden = true
        unitToPicker.hidden = true
        unitTypePicker.reloadAllComponents()
        unitFromLabel.text = ""
        unitToLabel.text = ""
    }
    @IBAction func unitFromBTN(sender: AnyObject) {
        unitTypePicker.hidden = true
        unitFromPicker.hidden = false
        unitToPicker.hidden = true
        unitFromPicker.reloadAllComponents()
    }
    @IBAction func unitToBTN(sender: AnyObject) {
        unitTypePicker.hidden = true
        unitFromPicker.hidden = true
        unitToPicker.hidden = false
        unitToPicker.reloadAllComponents()
    }



    // First Array for Unit Type
    let UnitDataArray = ["Unit for Weight","Unit for Length","Unit for Area","Unit for Volume","Unit for Quantity"]
    // Sec Array for Unit Type from or to
    let UnitforLengthData = ["m","km","cm","mm","yd","ft","in"]
    let UnitforWeightData = ["g","kg","m.t","l.t","sh.t","lb"]
    let UnitforArea = ["sq.m","sq.ft","sq.yd","sq.in"]
    let UnitforVolume = ["L","ml","gal","bu","cu.m","cu.in","cu.in."]
    let UnitforQuantity = ["pcs","pkg","pair","set","dozen","gross","ream","roll","unit","carton","bale","barrel","bag"]

    override func viewDidLoad() {
        super.viewDidLoad()


        //textinput.delegate = self
        //self.view.addSubview(textinput)

        unitTypeLabel.text = "Unit for Weight"
        unitTypeLabel.font = UIFont(name: "HelveticaNeue-Thin", size: 30)
        unitFromLabel.font = UIFont(name: "HelveticaNeue-Thin", size: 17)
        unitToLabel.font = UIFont(name: "HelveticaNeue-Thin", size: 17)
        //unitType delegate and datasource
        unitTypePicker.delegate = self
        unitTypePicker.dataSource = self
        //unitFrom delegate and datasource
        unitFromPicker.delegate = self
        unitFromPicker.dataSource = self
        //unitTo delegate and datasource
        unitToPicker.delegate = self
        unitToPicker.dataSource = self

        // pickerView hidden
        unitFromPicker.hidden = true
        unitToPicker.hidden = true
        unitTypePicker.hidden = true

        // Do any additional setup after loading the view, typically from a nib.
    }

    func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
        return 1
    }

    func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        if pickerView == unitTypePicker {
            return UnitDataArray.count
        }else if pickerView == unitFromPicker {
            if unitTypeLabel.text == "Unit for Weight" {
                return UnitforWeightData.count

            }else if unitTypeLabel.text == "Unit for Length" {
                return UnitforLengthData.count
            }else if unitTypeLabel.text == "Unit for Area" {
                return UnitforArea.count
            }else if unitTypeLabel.text == "Unit for Volume" {
                return UnitforVolume.count
            }else{
                return UnitforQuantity.count
            }
        }else{
            if unitTypeLabel.text == "Unit for Weight" {
                return UnitforWeightData.count

            }else if unitTypeLabel.text == "Unit for Length" {
                return UnitforLengthData.count
            }else if unitTypeLabel.text == "Unit for Area" {
                return UnitforArea.count
            }else if unitTypeLabel.text == "Unit for Volume" {
                return UnitforVolume.count
            }else{
                return UnitforQuantity.count
            }

        }
    }
    func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        if pickerView == unitTypePicker {
            return UnitDataArray[row]
        }else if pickerView == unitFromPicker {
            if unitTypeLabel.text == "Unit for Weight" {
                return UnitforWeightData[row]
            }else if unitTypeLabel.text == "Unit for Length" {
                return UnitforLengthData[row]
            }else if unitTypeLabel.text == "Unit for Area" {
                return UnitforArea[row]
            }else if unitTypeLabel.text == "Unit for Volume" {
                return UnitforVolume[row]
            }else{
                return UnitforQuantity[row]
            }

        }else{
            if unitTypeLabel.text == "Unit for Weight" {
                return UnitforWeightData[row]
            }else if unitTypeLabel.text == "Unit for Length" {
                return UnitforLengthData[row]
            }else if unitTypeLabel.text == "Unit for Area" {
                return UnitforArea[row]
            }else if unitTypeLabel.text == "Unit for Volume" {
                return UnitforVolume[row]
            }else{
                return UnitforQuantity[row]
            }

        }

    }
    func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        if pickerView == unitTypePicker{
            unitTypeLabel.text = UnitDataArray[row]
        }else if pickerView == unitFromPicker {
            if unitTypeLabel.text == "Unit for Weight"{
                unitFromLabel.text = UnitforWeightData[row]
            }else if unitTypeLabel.text == "Unit for Length" {
                unitFromLabel.text = UnitforLengthData[row]
            }else if unitTypeLabel.text == "Unit for Area" {
                unitFromLabel.text = UnitforArea[row]
            }else if unitTypeLabel.text == "Unit for Volume" {
                unitFromLabel.text = UnitforVolume[row]
            }else{
                unitFromLabel.text = UnitforQuantity[row]
            }
        }else{
            if unitTypeLabel.text == "Unit for Weight"{
                unitToLabel.text = UnitforWeightData[row]
            }else if unitTypeLabel.text == "Unit for Length" {
                unitToLabel.text = UnitforLengthData[row]
            }else if unitTypeLabel.text == "Unit for Area" {
                unitToLabel.text = UnitforArea[row]
            }else if unitTypeLabel.text == "Unit for Volume" {
                unitToLabel.text = UnitforVolume[row]
            }else{
                unitToLabel.text = UnitforQuantity[row]
            }
        }
    }

    func translet(number:Double,from:String,to:String) -> Double {
        switch from{
        case "g":
            return number
        case "kg":
            return number * 1000
        default:
            return number
        }
    }

}