UITextField - Allow only numbers and punctuation input/keypad

Question

I have tried the code below but that only allows for numbers on the keypad to be inputted. My app requires the keypad to use a period/full stop (for money transactions). The

Answer 1

In Swift 3:

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    let allowedCharacters = "0123456789!@#$%^&*()_+~:{}|\"?><\\`,./;'[]=-"
    return allowedCharacters.contains(string) || range.length == 1
}