Selecting the non-duplicate elements in the DataTable

Question

HI

I want to choose non-duplicate elements in DataTable

Where DataTable contains data as follows

TABLE A
COLUMN A

AM1
AM5
AM6
AM5
AM1
AM1
AM1

Where the final output is datatable= AM6

Blockquote

Public Function RemoveDuplicateRowsG(ByVal dTable As DataTable) As DataTable

    For intI = dTable.Rows.Count - 1 To 0 Step -1
        For intJ = intI - 1 To 0 Step -1
            If dTable.Rows(intI)(0) = dTable.Rows(intJ)(0) Then
                dTable.Rows.RemoveAt(intI)
                dTable.Rows.RemoveAt(intJ)
                Exit For

            End If
        Next
    Next

    dTable.AcceptChanges()
    Return dTable
End Function

Answer 1

It seems that you are also interested in fixing your loops. Consider this approach too:

dTable.AcceptChanges()

For i = 0 To dTable.Rows.Count - 1
    If dTable.Rows(i).RowState = DataRowState.Deleted Then Continue For
    Dim v = dTable.Rows(i)(0).ToString
    For j = i + 1 To dTable.Rows.Count - 1
        If dTable.Rows(j).RowState = DataRowState.Deleted Then Continue For
        If dTable.Rows(j)(0).ToString = v Then
            dTable.Rows(j).Delete()
            dTable.Rows(i).Delete()
        End If
    Next
Next

dTable.AcceptChanges()

Answer 2

Hi,
you can use LinQ expression like in following console demo:

Module Module73
  Sub Main()
    Try
      Dim c As New Demo
      c.Execute()
    Catch ex As Exception
      Console.WriteLine(ex.ToString)
    End Try
    Console.WriteLine("Continue enter key")
    Console.ReadKey()
  End Sub
  Friend Class Demo

    Friend Sub Execute()
      Try
        Dim dTable As DataTable = GetDataTable()


        Dim q = From row In dTable.AsEnumerable Group row By Key = row(0) Into Group Where Group.Count = 1 Select result = Key


        For Each r In q
          Console.WriteLine(r)
        Next
      Catch ex As Exception
        Console.WriteLine(ex.Message)
      End Try
    End Sub

    Private Function GetDataTable() As DataTable
      Dim str() As String = New String() {"AM1", "AM5", "AM6", "AM5", "AM1", "AM1", "AM1"}
      Dim dt As New DataTable("TableA")
      dt.Columns.Add("ColumnA", GetType(String))
      For Each item In str
        dt.Rows.Add(item)
      Next
      Return dt
    End Function

  End Class
End Module

Result:

AM6
Continue enter key