Question

I use the following coding which edits my text file based on the value in column being smaller than the value in a textbox.

Dim intValue As Integer
        Dim intMaxValue As Integer = Integer.Parse(textbox1.Text)

        Dim strSourceFile As String = IO.Path.Combine("G:\test.txt")
        Dim OutPutFile As String = IO.Path.Combine("G:\test2.txt")

        Dim strLines() As String = IO.File.ReadAllLines(strSourceFile)
        Dim strFiltered As New System.Text.StringBuilder
        Dim strTemp() As String

        For Each strLine In strLines
            If strLine.Trim.Length <> 0 Then
                strTemp = strLine.Split(" "c)
                If Trim(strTemp(0)) = "USER" AndAlso Trim(strTemp(2)) = "1" Then
                    strLine = strTemp(8).Trim & " " & strTemp(16).Trim
                    If Integer.TryParse(strLine.Split(" "c)(1), intValue) Then
                        If intValue <= intMaxValue Then
                            strFiltered.Append(strLine & Environment.NewLine)
                        End If
                    End If
                End If
            End If

        Next

        IO.File.WriteAllText(OutPutFile, strFiltered.ToString)

Now the above coding works perfectly, the output looks like the following:-

String1 100
String1 256
String1 500
String2 100
String2 256
String3 876
String3 345
String3 643
String3 102
String4 100
String4 084
String5 492
String5 178
String6 873
String6 156
String6 786

What I was hoping for was to add additional coding so i only want the String with the highest number showing so the above would look like

String1 500
String2 256
String3 876
String4 100
String5 492
String6 873

Would it be possible to add the final bit of coding?

UPDATE

Rather than checking the highest number and deleting the other fields, I wish to check each matching field in column 1 and check the highest number and if its greater than the field in textbox1 then remove all rows for that matching fields in column 1. If the highest number is lower than the field in textbox1, then keep that row but remove the other column 1 matching fields. So for example

String1 100
String1 256
String1 500
String2 100
String2 256
String3 876
String3 345
String3 643
String3 102
String4 100
String4 084
String5 492
String5 178
String6 873
String6 156
String6 786

So if textbox1 was to have 550 then you should have

String1 500
String2 256
String4 100
String5 492

Update 2

The value in textbox1 is

1341273599

When I only filter the columns to show column 1 and column 2 I get the following.

S00048 1428142557
S00048 1428141809
S00048 1338805621
S00048 1310295931
S00048 1309086124
S00048 1432203954
S00048 1431686625
S00048 1428142556
S00048 1431686626
S00048 1334743408
S00042 1324204635
S00040 1313659927
S00037 1308388943
S00033 1303118141
S00032 1391422317
S00032 1391422304
S00032 1298024019
S00032 1391422303
S00032 1391422316

So when I run the actual coding I get the following

S00048 1338805621
S00042 1324204635
S00040 1313659927
S00037 1308388943
S00033 1303118141
S00032 1298024019

You might be able to see that the end result is incorrect?

Answer 1

You could use a Dictionary to hold the values:

    Dim FilteredDictionary as new Dictionary(string, integer)

    Dim intValue As Integer
    Dim intMaxValue As Integer = Integer.Parse(textbox1.Text)

    Dim strSourceFile As String = IO.Path.Combine("G:\test.txt")
    Dim OutPutFile As String = IO.Path.Combine("G:\test2.txt")

    Dim strLines() As String = IO.File.ReadAllLines(strSourceFile)
    Dim strFiltered As New System.Text.StringBuilder
    Dim strTemp() As String

    Dim lastIntValue as integer = 0
    For Each strLine In strLines
        If strLine.Trim.Length <> 0 Then
            strTemp = strLine.Split(" "c)
            If Trim(strTemp(0)) = "USER" AndAlso Trim(strTemp(2)) = "1" Then
                strLine = strTemp(8).Trim & " " & strTemp(16).Trim
                If Integer.TryParse(strLine.Split(" "c)(1), intValue) Then
                      If intValue = 0 Then
                        intValue=lastIntValue
                      Else
                        lastIntValue=intValue
                      End If
                      If FilteredDictionary.ContainsKey(strTemp(8).Trim) then
                        If intValue > FilteredDictionary(strTemp(8).Trim) then
                          FilteredDictionary(strTemp(8).Trim) = intValue
                        End If
                      Else
                        FilteredDictionary.Add(strTemp(8).Trim, intValue)
                      End If
                        'strFiltered.Append(strLine & Environment.NewLine)

                End If
            End If
        End If
    Next

    'Modifed stringbuilder to only add those items that are less than or equal to
    'a given value in Textbox1.  Note that if Textbox1 is not an integer,
    'it will throw an error.  You could use Integer.TryParse instead.
    For Each item As String in FilteredDictionary.Keys.ToList
       If FilteredDictionary(item) <= Convert.ToInt32(Textbox1.Text)
         strFiltered.AppendLine(item & " " & FilteredDictionary(item))
       EndIf
    Next
    IO.File.WriteAllText(OutPutFile, strFiltered.ToString)