Delete columns from CSV then save in different folder path

Question

I need a script that opens a CSV from a specific file path, deletes specific columns and then exports the CSV to a specified folder.

Due to other scripts that will be integrated with this at a later stage, I have decided to do this using C#.

I have previously used Perl and achieved the desired result, but it isn't suitable for my application.

I found this link where I found this code;

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace CSV
{
class CSV
{
    private Dictionary<Tuple<int, int>, string> _data;
    private int _rows;
    private int _cols;

    public int Rows { get { return _rows; } }
    public int Cols { get { return _cols; } }

    public CSV()
    {
        Clear();
    }

    public void Clear()
    {
        _rows = 0;
        _cols = 0;
        _data = new Dictionary<Tuple<int, int>, string>();
    }

    public void Open(StreamReader stream, char delim = ',')
    {
        string line;
        int col = 0;
        int row = 0;

        Clear();

        while ((line = stream.ReadLine()) != null)
        {
            if (line.Length > 0)
            {
                string[] values = line.Split(delim);
                col = 0;
                foreach (var value in values)
                {
                    this[col, row] = value;
                    col++;
                }
                row++;
            }
        }
        stream.Close();
    }

    public void Save(StreamWriter stream, char delim = ',')
    {
        for (int row = 0; row < _rows; row++)
        {
            for (int col = 0; col < _cols; col++)
            {
                stream.Write(this[col, row]);
                if (col < _cols - 1)
                {
                    stream.Write(delim);
                }
            }
            stream.WriteLine();
        }
        stream.Flush();
        stream.Close();
    }

    public string this[int col, int row]
    {
        get
        {
            try
            {
                return _data[new Tuple<int, int>(col, row)];
            }
            catch
            {
                return "";
            }
        }

        set
        {
            _data[new Tuple<int, int>(col, row)] = value.ToString().Trim();
            _rows = Math.Max(_rows, row + 1);
            _cols = Math.Max(_cols, col + 1);
        }
    }

    static void Main(string[] args)
    {
        CSV csv = new CSV();

        csv.Open(new StreamReader(@"C:\mid\Dev\CSV_Splitter\VR_Path\New\Import_User_Sample_en.csv"));


        csv[0, 0] = "Column0";
        csv[1, 1] = "100";
        csv[2, 2] = "200";
        csv[3, 3] = "300";
        csv[4, 4] = "400";




csv.Save(new StreamWriter(@"C:\mid\Dev\CSV_Splitter\VR_Path\Proccessed\test_out.csv"));
    }
}
}

This uses C# to open a CSV file, manipulate it and save it in a new path.

I want to delete columns 0, 1, 2 and 3 from the csv file instead of manipulating the data.

Can anyone help?

Dipen Shah · Accepted Answer · 2018-11-29 12:43:01Z

2

You can use code you posted, just change Save method, initialize col variable with 4 and you should be done.

public void Save(StreamWriter stream, char delim = ',')
{
    if(_cols > 4) 
    {
    for (int row = 0; row < _rows; row++)
    {
        for (int col = 4; col < _cols; col++)
        {
            stream.Write(this[col, row]);
            if (col < _cols - 1)
            {
                stream.Write(delim);
            }
        }
        stream.WriteLine();
    }
    }
    stream.Flush();
    stream.Close();
}

Update:

To exclude 10th column, skip writing data in the 10th position.

public void Save(StreamWriter stream, char delim = ',')
{
    if(_cols > 4) 
    {
    for (int row = 0; row < _rows; row++)
    {
        for (int col = 4; col < _cols; col++)
        {
            if(col != 10)
            {
                stream.Write(this[col, row]);
                if (col < _cols - 1)
                {
                    stream.Write(delim);
                }
            }
        }
        stream.WriteLine();
    }
    }
    stream.Flush();
    stream.Close();
}

edited Nov 29, 2018 at 12:43

answered Nov 28, 2018 at 23:52

Dipen Shah

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3 Comments

Joshua McBride Over a year ago

I just made this amend and achieved the desired outcome, just out of curiousity, how would I proceed if I wished to remove column 10 also?

Dipen Shah Over a year ago

You will have to add if cause inside inner loop to skip that column.

Joshua McBride Over a year ago

Would this be inside the if (col < _cols - 1) { stream.Write(delim); } clause?

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