如何在Swift中从UI标签中删除字符？

Question

I am new to Swift and I am having issues with deleting a character from a UI Label that I have created. I am trying to make a simple phone dailer app, and I am trying ti implement a backspace button. My UI Label is called DailerLabel, and I know I'm supposed to use the dropLast() function but I keep running into issues about mismatching types or unwrappers. I am not really sure what I am supposed to do here. I tried the thing in the commented code which didn't work, and then I tried what I listed below which doesn't either. Could anyone help me?

    @IBAction func backspaceButtonPressed(_ sender: UIButton) {
    if (!((DailerLabel.text?.isEmpty)!)) {

       // DailerLabel.text?.substring(to: (DailerLabel.text?.index(before: (DailerLabel.text?.endIndex)!))!)

        let temp = DailerLabel.text
        temp?.dropLast()
        DailerLabel.text = temp

    }

Answer 1

You can try this one, replace label with your own UILabel

var name: String = label.text! //shauket , for example 
name.remove(at: name.index(before: name.endIndex))
print(name)    //shauke

label.text = name
print(label.text!)

Answer 2

You are very close. dropLast actually returns the string without the last character and you haven't stored that to anything so there is no change. You also have to conver back to String from Substring.

@IBAction func backspaceButtonPressed(_ sender: UIButton) {
    if (!((DailerLabel.text?.isEmpty)!)) {
        let temp = DailerLabel.text ?? ""
        DailerLabel.text = String(temp.dropLast())
    }
}

Here's a better version

@IBAction func backspaceButtonPressed(_ sender: UIButton) {
    guard
        let text = dialerLabel.text,
        !text.isEmpty
    else {
        return
    }
    dialerLabel.text = String(text.dropLast())
}