iOS 上的字符串到电话号码格式

Swift
func formatPhoneNumber(_ phoneNumber: String) -> String {
    // 去除字符串中的非数字字符
    let cleanedPhoneNumber = phoneNumber.replacingOccurrences(of: "[^0-9]", with: "", options: .regularExpression)
    
    // 判断字符串的长度
    let length = cleanedPhoneNumber.count
    
    // 根据字符串的长度进行不同的格式化
    if length == 7 {
        let startIndex = cleanedPhoneNumber.index(cleanedPhoneNumber.startIndex, offsetBy: 3)
        let endIndex = cleanedPhoneNumber.index(cleanedPhoneNumber.startIndex, offsetBy: 6)
        let areaCode = cleanedPhoneNumber[cleanedPhoneNumber.startIndex..<startIndex]</p>        let number = cleanedPhoneNumber[startIndex...endIndex]
        return "\(areaCode)-\(number)"
    } else if length == 10 {
        let startIndex = cleanedPhoneNumber.index(cleanedPhoneNumber.startIndex, offsetBy: 0)
        let endIndex = cleanedPhoneNumber.index(cleanedPhoneNumber.startIndex, offsetBy: 2)
        let areaCode = cleanedPhoneNumber[startIndex..<endIndex]</p>        let startIndex2 = cleanedPhoneNumber.index(cleanedPhoneNumber.startIndex, offsetBy: 3)
        let endIndex2 = cleanedPhoneNumber.index(cleanedPhoneNumber.startIndex, offsetBy: 6)
        let number = cleanedPhoneNumber[startIndex2...endIndex2]
        let startIndex3 = cleanedPhoneNumber.index(cleanedPhoneNumber.startIndex, offsetBy: 7)
        let endIndex3 = cleanedPhoneNumber.index(cleanedPhoneNumber.startIndex, offsetBy: 9)
        let number2 = cleanedPhoneNumber[startIndex3...endIndex3]
        return "(\(areaCode)) \(number)-\(number2)"
    } else {
        return cleanedPhoneNumber
    }
}
// 测试代码
let phoneNumber1 = "1234567"
let phoneNumber2 = "1234567890"
let formattedPhoneNumber1 = formatPhoneNumber(phoneNumber1)
let formattedPhoneNumber2 = formatPhoneNumber(phoneNumber2)
print(formattedPhoneNumber1) // 输出：123-4567
print(formattedPhoneNumber2) // 输出：(123) 456-7890