这是我的
Data例行十六进制字符串：
extension String { /// Create `Data` from hexadecimal string representation /// /// This creates a `Data` object from hex string. Note, if the string has any spaces or non-hex characters (e.g. starts with '<' and with a '>'), those are ignored and only hex characters are processed. /// /// - returns: Data represented by this hexadecimal string. var hexadecimal: Data? { var data = Data(capacity: characters.count / 2) let regex = try! NSRegularexpression(pattern: "[0-9a-f]{1,2}", options: .caseInsensitive) regex.enumerateMatches(in: self, range: NSRange(startIndex..., in: self)) { match, _, _ in let byteString = (self as NSString).substring(with: match!.range) let num = UInt8(byteString, radix: 16)! data.append(num) } guard data.count > 0 else { return nil } return data }}为了完整起见，这是我
Data的十六进制字符串例程：
extension Data { /// Hexadecimal string representation of `Data` object. var hexadecimal: String { return map { String(format: "%02x", $0) } .joined() }}请注意，如上所示，我通常只在十六进制表示形式和
NSData实例之间进行转换（因为如果可以将信息表示为字符串，则可能一开始就不会创建十六进制表示形式）。但是您最初的问题是要在十六进制表示形式和
String对象之间进行转换，因此可能看起来像这样：
extension String { /// Create `String` representation of `Data` created from hexadecimal string representation /// /// This takes a hexadecimal representation and creates a String object from that. Note, if the string has any spaces, those are removed. Also if the string started with a `<` or ended with a `>`, those are removed, too. /// /// For example, /// /// String(hexadecimal: "<666f6f>") /// /// is /// /// Optional("foo") /// /// - returns: `String` represented by this hexadecimal string. init?(hexadecimal string: String, encoding: String.Encoding = .utf8) { guard let data = string.hexadecimal() else { return nil } self.init(data: data, encoding: encoding) } /// Create hexadecimal string representation of `String` object. /// /// For example, /// /// "foo".hexadecimalString() /// /// is /// /// Optional("666f6f") /// /// - parameter encoding: The `String.Encoding` that indicates how the string should be converted to `Data` before performing the hexadecimal conversion. /// /// - returns: `String` representation of this String object. func hexadecimalString(encoding: String.Encoding = .utf8) -> String? { return data(using: encoding)? .hexadecimal }}然后可以像上面这样使用上面的代码：
let hexString = "68656c6c 6f2c2077 6f726c64"print(String(hexadecimal: hexString))
要么，
let originalString = "hello, world"print(originalString.hexadecimalString())
有关上述对早期Swift版本的排列，请参阅此问题的修订历史记录。
