Hi,

I want to know the easiest way to remove the last line in a text file, or
how to catch the last line of a text file. Thanks in advance

theres no function like "LastLine"...you have to read in each line and keep
track of where you are in the file

I built the function by myself as below:

Function RemoveNLinesFromFile(ByVal _Filename As String, ByVal
_LinesToRemove As Integer) As String

        Dim f As FileStream
        Dim CurrentPosition
        Dim LinesFound As Integer = 0
        Dim rval As String = ""
        Dim ch As Byte

        Try

            f = File.Open(_Filename, FileMode.Open)
            CurrentPosition = f.Length - 1

            While (CurrentPosition >= 0 And LinesFound < _LinesToRemove)
                f.Position = CurrentPosition
                ch = f.ReadByte()
                'rval += Convert.ToChar(s.ReadByte)
                'Debug.WriteLine("Position: " & s.Position & ", Value: " &
Convert.ToChar(s.ReadByte))
                If ch = 13 Then 'line feed
                    LinesFound += 1
                    If LinesFound >= _LinesToRemove Then
                        Exit While
                    End If
                Else
                    If LinesFound < 1 Then
                        'Debug.WriteLine(Convert.ToChar(ch))
                        rval = CStr(Convert.ToChar(ch)) + rval
                    End If
                End If
                CurrentPosition -= 1
            End While

            If CurrentPosition < 0 Then
                'MsgBox("Not enough lines in file to remove " &
_LinesToRemove & " lines, only found " & LinesFound & " lines")
                rval = "FAILED"
            Else
                f.SetLength(CurrentPosition + 2)
            End If
        Catch ex As Exception
            Return "FAILED" & ex.Message
        Finally
            f.Close()
        End Try

        If rval <> "FAILED" Then
            rval = Mid(rval, 2, Len(rval))
        End If

        Return rval

    End Function

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Hello Li,

Wow.  That's a lotta code just to remove a couple lines.  Plus it will only
work on ascii encoded files.
Try reading the entire file in, split the text on newline chars, then join
the lines back together using String.Join.  Not super efficient but the code
is easy to read and maintain.  If speed or memory consumption becomes an
issue you can look into optimization techniques.

-Boo

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