how to return first 2 columns &last 10 columnsfrom datatable

Ravi gaddam

Hi guys,

one datatable having 18 columns totally,but my question is ..how to return first 2 columns and last 10 columns from datatable. but actually it was used for other purpose earlier.eventually,returned datatable should not have middle 6 columns.

Thanks

Ravi Gaddam

3 Replies

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Ravi gaddam13y ago
Hi vishal Gilbile / Shankar,

Thanks a lot for spending time.

Regards
Ravi Gaddam
Shankar M13y ago
Hi Ravi,

You can Use Specific columns from DataTable using, DataTable ToTable method of the DatTable. Some thing like this,

Presume that, dtOriginal is a DataTable with 10 columns(col1,col2 ... col10) , To select
specific column from a DataTable to new DataTable we use,

DataTable dtOriginal = new DataTable();
dtOriginal.Columns.Add("col1");
dtOriginal.Columns.Add("col2");
dtOriginal.Columns.Add("col3");
dtOriginal.Columns.Add("col4");
dtOriginal.Columns.Add("col5");
dtOriginal.Columns.Add("col6");
dtOriginal.Columns.Add("col7");
dtOriginal.Columns.Add("col8");
dtOriginal.Columns.Add("col9");
dtOriginal.Columns.Add("col10");

DataTable dt = dtOriginal.DefaultView.ToTable(false,new string[] { "col1","col2","col3","col7","col10"});

Here in dt, we select only the columns col1,col2,col3,col7,col10 from the original DataTable
dtOriginal.
Vishal Gilbile13y ago
Following are the ways for doing it.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;

namespace testDataTable
{
class Program
{
DataTable dt;

public Program()
{
dt = CreateDataTableData();
//let's say i dont need column no 2 and 3
//there are two ways for doing it either use index no of the column or if you are having
// column names use a for loop like the following

//Way 1: removing with index no
//dt.Columns.RemoveAt(2);

//Way 2: removing with column names
//string[] obsoleteCols = { "Col2", "Col3" };

//foreach (string str in obsoleteCols)
//{
// dt.Columns.Remove(str);
//}

//Way3: making use of linq queries
DataTable linqDataTable = new DataTable();
var query = from data in dt.AsEnumerable() select new { Col1 = data[0], Col4 = data["Col4"], Col3 = data["Col5"] };
linqDataTable.Columns.Add("Col1");
linqDataTable.Columns.Add("Col4");
linqDataTable.Columns.Add("Col5");

foreach (var res in query)
{
DataRow dr = linqDataTable.NewRow();
dr[0] = res.Col1;
dr[1] = res.Col3;
dr[2] = res.Col4;
linqDataTable.Rows.Add(dr);
}

//finally display the output for the same.

}

private DataTable CreateDataTableData()
{
string[] colNames = { "Col1", "Col2", "Col3", "Col4", "Col5" };
string[,] colValues = { { "1", "2", "3", "4", "5" }, { "6", "7", "8", "9", "10" }, { "11", "12", "13", "14", "15" }, { "16", "17", "18", "19", "20" } };

DataTable newDt = new DataTable();

foreach (string str in colNames)
{
newDt.Columns.Add(str);
}

for (int i = 0; i < colValues.GetLength(0); i++)
{
DataRow dr = newDt.NewRow();
for (int j = 0; j < 5; j++)
{
dr[j] = colValues[i, j];
}
newDt.Rows.Add(dr);
}
return newDt;
}

static void Main(string[] args)
{
Program obj = new Program();
}
}
}
Hope it solves your problem