Number validation

numberValidation.swift

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    let newText = ((textField.text as NSString?) ?? "").replacingCharacters(in: range, with: string)
    guard newText.count > 0 else {
        return true
    }
    guard (newText.filter{ $0 == Character(Locale.current.decimalSeparator!) } as [Character]).count <= 1 else { // Make sure we only have one decimal separator
        return false
    }
    let numbersSet: Set<Character> = ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"]
    var withoutSeperator = newText
    if let separatiorIndex = withoutSeperator.index(of: Character(Locale.current.decimalSeparator!)) {
        withoutSeperator.remove(at: separatiorIndex)
    }
    return Set(withoutSeperator).isSubset(of: numbersSet)
}