Swift word processing - swift

Question

I'm making a simple swift application. Right now I have an input text field that takes a user input and outputs it to the output user field when a button is clicked. As shown in the code below:
import UIKit
import Foundation
class ViewController: UIViewController {
#IBOutlet weak var userNameField: UITextField!
#IBOutlet weak var textView: UITextView!
override func viewDidLoad() {
super.viewDidLoad()
userNameField.delegate = self
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
#IBAction func enterTapped(_ sender: Any) {
textView.text = "\(userNameField.text!)"
}
}
extension ViewController : UITextFieldDelegate {
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
}
I wanted to perform some word processing before the text is displayed to the user but, every time I try coding I get a bunch of errors. Where in the code should my word processing code go. When I refer to word processing I'm referring to some string commands such as: split, combine...

Answer 1

It should be here
#IBAction func enterTapped(_ sender: Any) {
let str = userNameField.text!
// do what you want with str
let addComma = str + ","
textView.text = addComma
}

Answer 2

Where in the code should my word processing code go.
you want to do some processing and put the processed text in the out-filed. As this process needs to take place on button action. I understand the processing should go in following method:
#IBAction func enterTapped(_ sender: Any) {
// this is the correct place for processing your string.
let inputStr = userNameField.text!
//Process 'inputStr" as needed.
textView.text = inputStr
}