C# reading a CSV file and parsing with linq

November 9, 2015 Uncategorized Comments Off on C# reading a CSV file and parsing with linq

I have a csv file that I need to read and wanted to parse the result using linq.

At first I was using the following:

public dynamic ReadCSVData(string path, bool firstRowFields = true)
{
    var query = from l in File.ReadAllLines(path)
                let f = l.Split(",".ToCharArray())
                select new
                {
                    Zero = f[0],
                    One = f[1],
                    Two = f[2],
                    Three = f[3],
                    Four = f[4],
                    Five = f[5],
                };
 
    return query.Skip(firstRowFields ? 1 : 0).ToList();
}

This reads data that only has the fields separated with just a comma.

The file I am reading also has fields that are enclosed with quotes.

After doing some research I came across the TextFieldParser in the Microsoft.VisualBasic.dll.

After adding the dll to the project I was able to adjust the code and now it looks as follows:

public dynamic ReadCSVData(string path, bool firstRowFields = true)
{
    dynamic data = null;
    // Have to add Microsoft.VisualBasic.dll to project
    using (var parser = new Microsoft.VisualBasic.FileIO.TextFieldParser(path))
    {
        parser.HasFieldsEnclosedInQuotes = true;
        parser.Delimiters = new[] { "," };
        var list = new List<string[]>();
        while (parser.PeekChars(1) != null)
        {
            string[] fields = parser.ReadFields();
            list.Add(fields);
        }
 
        var query = from f in list
                    select new
                    {
                        Zero = f[0],
                        One = f[1],
                        Two = f[2],
                        Three = f[3],
                        Four = f[4],
                        Five = f[5],
                    };
 
        data = query.Skip(firstRowFields ? 1 : 0).ToList();
    }
    return data;
}

The second method may not be usable if the file is large or fast parsing is needed.

For my project it is a small file and speed is not an issue.

This parses the file correctly as well as being part the .Net framework.

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