Unicode characters returning from R.NET

Question

I'm returning a Character vector from a function in R to C# using R.NET. The only problem is that unicode characters, such as Greek Letters are being lost. The following line gives an example of the code I'm using:

CharacterVector cvAll = results[5].AsList().AsCharacter();

Where results is a list of results returned by the R function. The characters are also written by R to a text file and they display fine in notepad and other editors. Can I get R.Net to return the characters correctly?

Answer 1

Looks like you ran into an open issue with RDotNet : https://github.com/jmp75/rdotnet/issues/25

Unicode characters don't seem to be supported yet. I ran into the same issue while calling the engine.CreateDataFrame() method. It did return a DataFrame with all my accentuated strings wrong.

There seems to be a workaround though : when calling RDotNet functions, if I give strings encoded in my computer default encoding (Windows ANSI) and converted from UTF-8 (important), R takes them and gives back correctly interpreted accentuated strings to C#. I don't exactly know why it is working though... It might have something to do with the default encoding used with .Net for string being UTF-16. (cf. here : http://csharpindepth.com/Articles/General/Strings.aspx), hence the conversion from UTF-8 to default ANSI that seems to be working.

Here is an ugly example : when I'm building a RDotNet DataFrame, I convert all strings in a CharacterVector to ANSI (from UTF-8) encoded ones :

try 
{
    string[] colAsStrings = null;
    colAsStrings = Array.ConvertAll<object, string>(uneColonne, s => StringEncodingHelper.EncodeToDefaultFromUTF8((string)s));
    correctedDataArray[i] = colAsStrings;
    columnConverted = true;
}

Here is the static method used for conversion :

public static string EncodeToDefaultFromUTF8(string stringToEncode)
{
    byte[] utf8EncodedBytes = Encoding.UTF8.GetBytes(stringToEncode);

    return Encoding.Default.GetString(utf8EncodedBytes);
}