Csv Convert Read line to double

Question

I am trying to read a csv file in to an data structure but I can't seem to convert it in to an double type.

static void Main(string[] args)
        {
            var reader = new StreamReader(File.OpenRead(@"E:\file.csv"));
            List<Double> close = new List<Double>();

            int counter = 0;


            while (!reader.EndOfStream)
            {
                counter = counter + 1;
                var line = reader.ReadLine();
                var values = line.Split(',');


                string str = values[4];
                Double val = Convert.ToDouble(str); //THIS IS THE PROBLEM

                Console.WriteLine(values[4].GetType());
            }

            // Prompt to Exit
            Console.WriteLine("Press any key to exit.");
            Console.Read();


        }

I get an error:

An unhandled exception of type 'System.FormatException' occurred in mscorlib.dll

Additional information: Input string was not in a correct format.

values[4] is of type System.string

Try this to parse `double.Parse(str,NumberStyles.Any, CultureInfo.InvariantCulture)` — Giorgos Betsos, Jan 30 '15 at 19:17
Well if you get a `FormatException`, the obvious question is: what is the value that's causing it to throw the exception? — mason, Jan 30 '15 at 19:17
possible duplicate of [Best way to parse command line arguments in C#?](http://stackoverflow.com/questions/491595/best-way-to-parse-command-line-arguments-in-c) — user1234440, Jan 30 '15 at 19:23
@user1234440 Why did you post that? This has nothing to do with parsing command line arguments. Update your question to include the value of `values[4]`. — mason, Jan 30 '15 at 19:48
Sorry guys, I found the problem. It was because I had a header. I just needed to skip the header and it worked. Thanks for all the help. — user1234440, Jan 30 '15 at 19:51

score 1 · Answer 1 · answered Jan 30 '15 at 19:17

'System.FormatException' indicates a run-time issue caused by the data in your CSV file, not by the code of your program.

It means that the item at index four does not represent a valid double value. For example, it could be an empty string, or some other non-numeric string. In order to diagnose this problem properly, add a try/catch around the call of Convert.ToDouble(str), and print the message when you get an exception:

Double val;
try {
    val = Convert.ToDouble(str);
} catch (FormatException fe) {
    Console.Error.WriteLine("Got {0} when processing '{1}'", fe.Message, str);
}

score 1 · Answer 2 · answered Jan 30 '15 at 19:19

1

Use the Double.Parse method. You can then provide NumberStyles corresponding to what's written in your .csv.

answered Jan 30 '15 at 19:19

Laurent Jalbert Simard

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Csv Convert Read line to double

2 Answers2