convert string array to float array in C#

Question

We are getting an error when trying to run this code ideally changes e.Message from string to a double or float array. Please help us understand what the error means, or how to debug the code.

We also tired a float.Parse(e.Message, CultureInfo.InvariantCulture.NumberFormat); method, which also resulted in an error.

private void ClientReceiveData(object sender, ConnectedClient.NetDataEventArgs e)
{
    if (string.IsNullOrEmpty(e.Message) == false)
    {
        if (e.ID == 0)
        {
            //float.Parse(e.Message, CultureInfo.InvariantCulture.NumberFormat);
            Array.ConvertAll(e.Message.Split(','), Double.Parse);
            Trace.WriteLine(String.Join(Environment.NewLine, e.Message));
        }

        if (e.ID == 1)
        {
            //float.Parse(e.Message, CultureInfo.InvariantCulture.NumberFormat);
            Array.ConvertAll(e.Message.Split(','), Double.Parse);
            Trace.WriteLine(String.Join(Environment.NewLine, e.Message));
        }
    }

INPUT (e.Message):

0.0160163, -0.3207418, -0.2747217, 0.9856872, -0.3428816, 0.02380935, 0.8472792, -0.3562718, 0.3080477, 0.6931204, -0.4135765, 0.2335226, 0.6617407, -0.2861188, 0.278595, 0.685502, -0.3337714, 0.06315409, 0.5661756, -0.5338272, 0.1274863, 0.6014508, -0.6020046, 0.149146, 0.6165056, -0.2287867, 0.108688, 0.753313, -0.2801398, 0.1555204, 0.5711947, -0.4046459, 0.3197014, 0.6477473, -0.4134837, 0.3147845, 0.6426268, -0.3393434, -0.242843, 0.9667573, -0.3945386, -0.2511228, 0.5462032, -0.4459318, -0.2613428, 0.2010812, -0.43355, -0.2804166, 0.09203719, -0.2818186, -0.2890762, 0.9426621, -0.2850094, -0.2625419, 0.5789056, -0.2990395, -0.2414854, 0.1805503, -0.2872439, -0.2554213, 0.06843466, -0.3543724, 0.2399589, 0.7335942, -0.5984071, 0.1476627, 0.6094998, -0.5848852, 0.1458522, 0.6007382, -0.4560334, 0.3629844, 0.6141819, -0.4130909, 0.2523528, 0.57725,

We need a minimal reproducible example included in your question. Include your actual input, not a screenshot from your IDE — maccettura
– maccettura, Commented Aug 24, 2018 at 16:58
Paste the entire contents of e.Message as plain text. There is something in there it doesn't like, and we can't see the entire thing. — Paul Abbott
– Paul Abbott, Commented Aug 24, 2018 at 17:01
BTW, ConvertAll returns a new array so if you don't assign the output to anything it won't be very useful. — Crowcoder
– Crowcoder, Commented Aug 24, 2018 at 17:05
You have a trailing comma, which is resulting in a blank entry from split. Use the RemoveEmptyEntries option. This is a good example of why we discourage screenshots of error messages. — Paul Abbott
– Paul Abbott, Commented Aug 24, 2018 at 17:09
@JayTailor The trailing comment is likely the problem, add the option StringSplitOptions.RemoveEmptyEntries — D Stanley
– D Stanley, Commented Aug 24, 2018 at 17:09

maccettura · Accepted Answer · 2018-08-24 17:15:44Z

10

The last entry is an empty string which will not parse with Double.Parse.

You may use:

var parsed = Array.ConvertAll(
    e.Message.Split(new[] { ',', }, StringSplitOptions.RemoveEmptyEntries),
    Double.Parse);

Also note that Double.Parse depends on the current CultureInfo for the interpretation of periods . in the strings.

edited Aug 24, 2018 at 17:15

maccettura

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answered Aug 24, 2018 at 17:10

Jeppe Stig Nielsen

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1 Comment

Jeppe Stig Nielsen Over a year ago

That depends. If the event handling method needs to run twice before you can find the "vector sum" final, you may have double[] answer; and double[] result; as fields (i.e. variable on the class-level, outside methods). Then you can calculate final from that after both fields have been assigned.

D Stanley · Accepted Answer · 2018-08-24 17:19:57Z

1

You need to be able to catch the offending value, and should ignore "empty" entries like the one created by the trailing comma:

private void ClientReceiveData(object sender, ConnectedClient.NetDataEventArgs e)
{
    double[] result = null; 
    if (string.IsNullOrEmpty(e.Message) == false)
    {
        if (e.ID == 0)
        {
            //float.Parse(e.Message, CultureInfo.InvariantCulture.NumberFormat);
            result = Array.ConvertAll(e.Message.Split(new [] {','}, StringSplitOptions.RemoveEmptyEntries), ParseWithError);
            Trace.WriteLine(String.Join(Environment.NewLine, e.Message));
        }

        if (e.ID == 1)
        {
            //float.Parse(e.Message, CultureInfo.InvariantCulture.NumberFormat);
            result = Array.ConvertAll(e.Message.Split( new [] {','}, StringSplitOptions.RemoveEmptyEntries), ParseWithError);
            Trace.WriteLine(String.Join(Environment.NewLine, e.Message));
        }
    }
}

double ParseWithError(string value) 
{
     double result;
     if (!double.TryParse(value, out result))
     {
         throw new ApplicationException("Error parsing value " + value,e);
     }
     return result;
}

edited Aug 24, 2018 at 17:19

answered Aug 24, 2018 at 17:07

D Stanley

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1 Comment

Jeppe Stig Nielsen Over a year ago

More nice in my opinion:

double ParseWithError(string value)  {     if (double.TryParse(value, out var dbl)) { return dbl; } throw new ApplicationException("Error parsing value " + value); }

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