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I have a very big csv file like this (more than 12K rows) ;

    Comment, DateTime   Name,  Age,  Class, Place,  --> these are the header columns
    Good,    03/10/2022, John,  12,    3,     UK,
    Bad,     12/10/2022, Tom,   15,    2,     US

This is a generalized example which shows column names. But it will be more than this columns some times.

I am reading it as shown below

    List<string> lines = File.ReadAllLines(System.IO.Path.ChangeExtension(FileNameWithPath, ".csv")).ToList();

I need a datatable from the above mentioned csv file but i DO NOT want Comment and Place columns in the datatable.

Can anybody show me how we can achieve this ?

Column datatypes :

       DateTime --> typeof(datetime)

       Name     --> typeof(string)

       Age --> typeof(double?)

       Class  --> typeof(int)
David Specht
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Micheal
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  • Does it need to be a DataTable? If you are open to using a class object, take a look at how you can [deserialize to a model in CsvHelper](https://stackoverflow.com/questions/61370447/c-sharp-csv-file-how-to-skip-few-columns-while-reading-csv-file-using-datatabl). Sorry but obligatory possible duplicate – Narish Oct 26 '22 at 15:23
  • @Narish buddy, we cannot predict the columns name and number of columns in advance. – Micheal Oct 26 '22 at 15:33
  • that sounds like a rough situation. Well in that case, only thing I can think of is to create the full data table and then you can use `dt.Columns.Remove("colNameString")` or `dt.Columns.RemoveAt(colIndex)`. Or for only one forward pass, build the datatable manually. Since you are getting the info in as `List` it seems like there is some data marshalling you are going to be doing in any case – Narish Oct 26 '22 at 15:37

2 Answers2

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You can remove the columns using DataColumnCollection.Remove() after converting from the list to a datatable.

dt.Remove("Comments")

stephemer
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public static DataTable CSVtoDataTable(string filePath)
  {
    DataTable dtData = new DataTable();
    using (StreamReader sReader = new StreamReader(filePath))
    {
        string[] columnHeader = sReader.ReadLine().Split(',');
        foreach (string header in columnHeader)
        {
            dtData.Columns.Add(header);
        }
        while (!sReader.EndOfStream)
        {
            string[] rows = sReader.ReadLine().Split(',');
            DataRow drRow = dtData.NewRow();
            for (int i = 0; i < columnHeader.Length; i++)
            {
                drRow[i] = rows[i];
            }
            dtData.Rows.Add(drRow);
        }

    }

    dtData.Columns.Remove("Comment");
    dtData.Columns.Remove("Place");
        return dtData;
   }
Zain Maqbool
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  • As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Oct 30 '22 at 00:53