Ios 编码UTF8返回零Swift3

我正在尝试使用Firebase下载一个csv文件，文件中的字符类似于«aä–a»。 如您所见，我使用的是Swift3编码功能：

字符串（字节：data！，编码：.utf8）

在我的代码中：

func downloadMyCSVWithDLURL(csvName: String, modeType: Bool, modeSync: Bool){
        let realm = try! Realm()

        //Firebase Storage Reference
        let storage = FIRStorage.storage()

        //Firebase Path to my csv file
        if (FIRAuth.auth()?.currentUser?.uid) != nil {
            let userID = FIRAuth.auth()?.currentUser?.uid
            let downloadRef = storage.reference(forURL:  "\(REF_USERS_CSV_FOLDER)").child("USERS_BDD_CSV/\(userID!)/\(csvName).csv")

            //Download csv file in "data" as NSData
            downloadRef.data(withMaxSize: 1000000, completion: { (data, err) in

                //Encoding
                let rawString = String(bytes: data!, encoding: .utf8)

                let rawLines = rawString?.components(separatedBy: ["\n"])
                let count = rawLines?.count
                var tableParticipant = [Participant]()

                for i in 1...count! {
                        let datas = rawLines![i].components(separatedBy: ";")
[...]
}

id;lastname;firstname;phoneNBR;mail;qrCode;address;cp;city;company;plusOne;entryType;eventName;isCheck;liveInscr;dateInscr;dateCheck
424ad79a;DOE;Johnàéèäâ;22222222222;doe@john.com;QRcode;14 George Street;2000;Sydney;COMPANY;;VIP;XXX;false;false;null;null

• 数据和数据！=1586ko字节，是我的csv的正确大小

我的CSV示例：

func downloadMyCSVWithDLURL(csvName: String, modeType: Bool, modeSync: Bool){
        let realm = try! Realm()

        //Firebase Storage Reference
        let storage = FIRStorage.storage()

        //Firebase Path to my csv file
        if (FIRAuth.auth()?.currentUser?.uid) != nil {
            let userID = FIRAuth.auth()?.currentUser?.uid
            let downloadRef = storage.reference(forURL:  "\(REF_USERS_CSV_FOLDER)").child("USERS_BDD_CSV/\(userID!)/\(csvName).csv")

            //Download csv file in "data" as NSData
            downloadRef.data(withMaxSize: 1000000, completion: { (data, err) in

                //Encoding
                let rawString = String(bytes: data!, encoding: .utf8)

                let rawLines = rawString?.components(separatedBy: ["\n"])
                let count = rawLines?.count
                var tableParticipant = [Participant]()

                for i in 1...count! {
                        let datas = rawLines![i].components(separatedBy: ";")
[...]
}

id;lastname;firstname;phoneNBR;mail;qrCode;address;cp;city;company;plusOne;entryType;eventName;isCheck;liveInscr;dateInscr;dateCheck
424ad79a;DOE;Johnàéèäâ;22222222222;doe@john.com;QRcode;14 George Street;2000;Sydney;COMPANY;;VIP;XXX;false;false;null;null

错误：

func downloadMyCSVWithDLURL(csvName: String, modeType: Bool, modeSync: Bool){
        let realm = try! Realm()

        //Firebase Storage Reference
        let storage = FIRStorage.storage()

        //Firebase Path to my csv file
        if (FIRAuth.auth()?.currentUser?.uid) != nil {
            let userID = FIRAuth.auth()?.currentUser?.uid
            let downloadRef = storage.reference(forURL:  "\(REF_USERS_CSV_FOLDER)").child("USERS_BDD_CSV/\(userID!)/\(csvName).csv")

            //Download csv file in "data" as NSData
            downloadRef.data(withMaxSize: 1000000, completion: { (data, err) in

                //Encoding
                let rawString = String(bytes: data!, encoding: .utf8)

                let rawLines = rawString?.components(separatedBy: ["\n"])
                let count = rawLines?.count
                var tableParticipant = [Participant]()

                for i in 1...count! {
                        let datas = rawLines![i].components(separatedBy: ";")
[...]
}

id;lastname;firstname;phoneNBR;mail;qrCode;address;cp;city;company;plusOne;entryType;eventName;isCheck;liveInscr;dateInscr;dateCheck
424ad79a;DOE;Johnàéèäâ;22222222222;doe@john.com;QRcode;14 George Street;2000;Sydney;COMPANY;;VIP;XXX;false;false;null;null

致命错误：在展开可选值时意外发现nil （lldb）

• 设rawString=nil
• 设rawLines=nil
• 让计数=零

如果我的变量是nil，那是因为我的csv中的“aèè–”，我猜编码失败并返回nil

顺便说一下，如果没有这个特殊字符，编码不会返回nil，我的应用程序运行得很好

为什么utf8编码失败

---

有人有什么建议吗？

你的CSV不是UTF8编码谢谢，你说得对，在将我的CSV文件重新编码为UTF8后，应用程序不会崩溃。但是出现的是特殊字符而不是正确的字符。因此，在读取

字符串（字节：数据，编码：。无论什么）

您的CSV不是UTF8编码谢谢，您是对的，将我的CSV文件重新编码为UTF8后，应用程序不再崩溃。但是会出现特殊字符而不是正确的字符。因此，在读取

字符串（字节：data，encoding:.whatever）时，只需使用原始编码方法