• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 290
  • Last Modified:

How to INSERT, SORT, FILTER a CSV file in VB.NET

I am trying to put to get a small program to randomly select a record from a CSV file.  The user would select the file and the program would filter the file on one column, insert a column of random numbers and then sort the file and select a number of record to be wirtten to an output file.

To select the file, I have the following:

 Private Sub btnBrowse1_Click(sender As Object, e As EventArgs) Handles btnBrowse1.Click
        Dim randomValue As Random = New Random
        Dim openFileDialog1 As New OpenFileDialog()


        openFileDialog1.Filter = "CSV Files|*.csv"
        openFileDialog1.Title = "Select a CSV File"

        Dim list As New List(Of String)

        If openFileDialog1.ShowDialog() = DialogResult.OK Then
            myFileName = openFileDialog1.FileName
            outputFile = myFileName.Replace(".csv", "_" & System.DateTime.Now.ToString("yyyyMMdd") & ".csv")
            txtCsvFile.Text = myFileName
        End If
    End Sub

To process the file I have this:

    Private Sub btnProcess_Click(sender As Object, e As EventArgs) Handles btnProcess.Click
        Dim sReader As StreamReader = New StreamReader(myFileName)
        Dim sWriter As StreamWriter = New StreamWriter(outputFile)
        Dim line As String
        Dim rv As Integer
        Dim recAmount As Integer
        Dim counter As Integer = 0

        ' Store contents in this String.
        ' Read first line.
        line = sReader.ReadLine
        recAmount = CInt(txtRecAmount.Text)

        MsgBox(randomValue.Next(1, 1000))

        ' Loop over each line in file, While list is Not Nothing.
        Do While sReader.Peek <> -1
            counter += 1
            line = sReader.ReadLine
            rv = randomValue.Next(1, 1000)

            Do While counter < recAmount + 1
                sWriter.WriteLine(rv & "," & line)
                Exit Do
                ' Read in the next line.
            Loop
        Loop
        sWriter.Close()
    End Sub

It doesn't filter or sort.  Do I need to read it into a two dimensional array? If so, how do I filter and sort the 2 dimensional array?
0
abuhaneef
Asked:
abuhaneef
1 Solution
 
Bob LearnedCommented:
You could use the TextFieldParser class to parse the CSV into separate elements, that you could sort on.

Example:

TextFieldParser Class
https://msdn.microsoft.com/en-us/library/microsoft.visualbasic.fileio.textfieldparser(v=vs.110).aspx

Using MyReader As New Microsoft.VisualBasic.FileIO.
    TextFieldParser("c:\logs\bigfile")

    MyReader.TextFieldType = 
        Microsoft.VisualBasic.FileIO.FieldType.Delimited
    MyReader.Delimiters = New String() {vbTab}
    Dim currentRow As String()
    'Loop through all of the fields in the file.  
    'If any lines are corrupt, report an error and continue parsing.  
    While Not MyReader.EndOfData
        Try
            currentRow = MyReader.ReadFields()
            ' Include code here to handle the row. 
        Catch ex As Microsoft.VisualBasic.FileIO.MalformedLineException
            MsgBox("Line " & ex.Message & 
            " is invalid.  Skipping")
        End Try 
    End While 
End Using

Open in new window

0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

Cloud Class® Course: Ruby Fundamentals

This course will introduce you to Ruby, as well as teach you about classes, methods, variables, data structures, loops, enumerable methods, and finishing touches.

Tackle projects and never again get stuck behind a technical roadblock.
Join Now