Why Is Uitextfield.Text an Optional

Why Is UITextField.text An Optional?

This is a historical thing. UITextField does not make any difference between an empty string and a nil string. In Objective-C there was no need to make a difference between them because you can call methods on nil in Objective-C.

Also, there was no way in Objective-C to prevent users from assigning nil to a property.
The resulting contract is that text can be optional. In Objective-C that makes no difference.

In Swift there is not much we can do because UITextField.text contract would have to change, possibly breaking lots of already written code. Note that even if nil is never returned from the method, you can still assign nil to reset the value.

You can find hundreds of similar situations in the old APIs.

Why does UITextFIeld return optional value in Swift?

The reason is probably because you're using shouldChangeCharactersIn which doesn't indicate the change in the character until the second character. Ideally you want the user to be notified of the correct answer after they complete the answer and submit it, in which case you want to use something like textFieldDidEndEditing:

class MyVC: UIViewController, UITextFieldDelegate {
    let textField = UITextField()
    var numberLabel: UILabel {
        let label = UILabel()
        label.text = "100"
        return label
    }
    let button = UIButton()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.addSubview(textField)
        textField.borderStyle = .roundedRect
        textField.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            textField.widthAnchor.constraint(equalToConstant: 200),
            textField.heightAnchor.constraint(equalToConstant: 100)
        ])
        textField.delegate = self
        
        button.addTarget(self, action: #selector(buttonPressed), for: .touchUpInside)
        button.tag = 1
        button.backgroundColor = .black
        button.setTitle("Answer", for: .normal)
        self.view.addSubview(button)
        button.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            button.leadingAnchor.constraint(equalTo: textField.trailingAnchor),
            button.widthAnchor.constraint(equalToConstant: 200),
            button.heightAnchor.constraint(equalToConstant: 100)
        ])
        
    }
    
    @objc func buttonPressed(_ sender: UIButton!) {
        if case let tag = sender.tag, tag == 1 {
            textField.resignFirstResponder()
        }
    }
    
    func textFieldDidEndEditing(_ textField: UITextField) {
        //convert string into number
        let input = (numberLabel.text! as NSString).integerValue
        
        //find answer to label when added by 1111
        let answer = input + 1111
                print(answer)
        
        if let numberText = Int(textField.text ?? "0") {
            print("This is number text: \(numberText)")
            
            if answer == numberText {
                //if user gets answer correct
                print("correct")
            } else {
                //if user gets answer incorrect
                print("wrong")
            }
        }
    }

}

Why does a UITextField have a .text value of Optional(Actual Text) Swift

Since your MyTextField is an optional, you will have to unwrap the value in your text before printing it.

override func viewDidLoad() {
    super.viewDidLoad()

    if let text = MyTextField.text {
        print(text)
    }
}

Force Unwrap Optionals from UITextfield

Simply use

self.name = NameInput.text!

or

self.name = NameInput.text ?? ""

Once you use String(describing:) the Optional(...) text will be part of your string rather than an optional string and you won't be able to remove it.

UITextField displaying Optional() before input

In the following code:

 var newString = textField.text

            if newString!.characters.count == 0 {
                newString = "\(newString)\(string)"
                shouldMoveToNextField = true
            }

Change...

newString = "\(newString)\(string)"

to....

newString = "\(string)"

Swift: How to unwrap UITextField Optional String to Float

Your calculation seems fine but it might be throwing a compiler error for setting Float in place of String to totalTipAmount. You can try as follows,

@objc func sliderChange() {
    guard let priceText = self.priceTextField.text, let price = Float(priceText) else { return }
    totalTipAmount.text = "\(tipSlider.value * price)"
}

Why is uitextfield not outputting optional?

The default value of UITextField is an empty string. so even if you have not typed anything the value is ""

If you want to check:

if let validPass = passwordInput.text {
   print("It is not optional")
} else {
   print("It is optional")
}

And you will see that output is "It is not optional"

If you want to check whether it is empty or not:

if let validPass = passwordInput.text, !validPass.isEmpty {
    print("It is not optional or not empty")
}

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