Phone number formatting

PhoneFormat.swift

    func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
        var length = getLength(textField.text)
        if length == 10 {
            if range.length == 0 {
                return false
            }
        }
        if length == 3 {
            var num = formatNumber(textField.text)
            textField.text = "(\(num))"
            if range.length > 0 {
                textField.text = (num as NSString).substringToIndex(3)
            }
        }
        else if length == 6 {
            var num = formatNumber(textField.text)
            textField.text = "(\((num as NSString).substringToIndex(3))) \((num as NSString).substringFromIndex(3))-"
            if range.length > 0 {
                textField.text = "(\((num as NSString).substringToIndex(3))) \((num as NSString).substringFromIndex(3))"
            }
        }
        return true
    }

    
    func getLength(string: String) -> Int {
        var str = removeNonNumber(string)
        
        return count(str)
    }
    
    func formatNumber(string: String) -> String {
        var str = removeNonNumber(string)
        
        var length = count(str)
        if length > 10 {
            str = (str as NSString).substringFromIndex(length - 10)
        }
        return str
    }
    
    func removeNonNumber(string: String) -> String {
        var str = string
        
        str = str.stringByReplacingOccurrencesOfString("(", withString: "", options: nil, range: nil)
        str = str.stringByReplacingOccurrencesOfString(")", withString: "", options: nil, range: nil)
        str = str.stringByReplacingOccurrencesOfString(" ", withString: "", options: nil, range: nil)
        str = str.stringByReplacingOccurrencesOfString("-", withString: "", options: nil, range: nil)
        str = str.stringByReplacingOccurrencesOfString("-", withString: "", options: nil, range: nil)
        str = str.stringByReplacingOccurrencesOfString("+", withString: "", options: nil, range: nil)
        
        return str
    }