Importing last line of a .csv file

Question

I have a csv file and I need to get the last line only into seperate textboxes.

Imports System.IO

Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    End Sub

    Private Sub btnConditions_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnConditions.Click
        Using reader As New StreamReader("C:\temp\Apr12log.txt")
            Dim line As String = reader.ReadLine()


            Dim fields() As String = line.Split(",".ToCharArray())
            Dim fileDate = CDate(fields(0))
            Dim fileTime = fields(1)
            Dim fileTemp = fields(2)
            Dim fileHum = fields(3)
            Dim fileWindSpeed = fields(4)
            Dim fileWindGust = fields(5)
            Dim fileWindBearing = fields(6)

            While line IsNot Nothing

                line = reader.ReadLine()
            End While
            txtDate.Text = CStr(fileDate)
        End Using

    End Sub

End Class

It only inputs the first line I am not sure how to get the last line only.

example of txtfile

01/04/12,00:00,5.4,80,3.0,4.5,9.6,261,0.0,0.0,1025.0,1.0,16.8,43,4.0,3.8,5.4,0.0,0,0.0

Is the .csv file small enough to be read into memory in one go, or is it a huge file? — Andrew Morton, Jun 25 '13 at 13:47
Although in c#, [this](http://stackoverflow.com/questions/11625595/read-last-line-of-text-file) answers what you are looking for. — shahkalpesh, Jun 25 '13 at 13:58
Note that VB has the `Microsoft.VisualBasic.FileIO.TextFieldParser` but that's probably overkill here. — Mark Hurd, Jun 25 '13 at 14:12
Thanks for your help everyone! I Just had to add this line and take out the while loop Dim lastLine = File.ReadLines("C:\temp\Apr12log.txt").Last() — yolad, Jun 25 '13 at 14:20

score 3 · Accepted Answer · answered Jun 25 '13 at 14:16

Alternatively, you could use the System.IO.File ReadLines() function, which gives you an enumerable that you can call Last() on.

Private Sub btnConditions_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnConditions.Click

        Dim line As String = System.IO.File.ReadLines("C:\temp\Apr12log.txt").Last()

        Dim fields() As String = line.Split(",".ToCharArray())
        Dim fileDate = CDate(fields(0))
        Dim fileTime = fields(1)
        Dim fileTemp = fields(2)
        Dim fileHum = fields(3)
        Dim fileWindSpeed = fields(4)
        Dim fileWindGust = fields(5)
        Dim fileWindBearing = fields(6)

        txtDate.Text = CStr(fileDate)

End Sub

score 1 · Answer 2 · answered Jun 25 '13 at 13:46

1

You're only reading in one line. Instead use ReadToEnd() and then split by a new line, like so:

Dim lines() As String = reader.ReadToEnd().Split(Environment.NewLine)

Then you can move to the last line:

Dim line As String = lines(lines.Length - 1)

answered Jun 25 '13 at 13:46

DAC84

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score 1 · Answer 3 · answered Jun 25 '13 at 13:52

1

You can get what you want with a couple of edits to your existing code:

Shift

   While line IsNot Nothing

        line = reader.ReadLine()
   End While

To just after

   Dim line As String = reader.ReadLine()

Add another

   Dim line2 As String = Nothing

And insert

       line2 = line

Into the While loop, i.e.

   While line IsNot Nothing
        line2 = line
        line = reader.ReadLine()
   End While

Now line2 is the last line in the file.

answered Jun 25 '13 at 13:52

Mark Hurd

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1

He also would need to move his reading of all the fields to after the while loop, which is why he's getting data from the first line. – Seth Moore Jun 25 '13 at 13:57
@smoore That's why my first lines say shift the `While` loop to just after the first `Dim`. – Mark Hurd Jun 25 '13 at 13:59
Indeed it does! Sorry I didn't follow that right. +1 for you sir! – Seth Moore Jun 25 '13 at 14:00
Thanks for your help everyone! I Just had to add this line and take out the while loop Dim lastLine = File.ReadLines("C:\temp\Apr12log.txt").Last() – yolad Jun 25 '13 at 14:22

score 0 · Answer 4 · answered Jun 25 '13 at 13:45

0

Try this:

Dim lines() As String = File.ReadAllLines("C:\temp\Apr12log.txt")

lastLine = lines(lines.Length - 1)

answered Jun 25 '13 at 13:45

SysDragon

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Importing last line of a .csv file

4 Answers4