Read 2nd-to-last Line Of A Very Large Log File
Oct 7, 2011
I need to read the second-to-last line of a very large log file.
I can't read the entire thing into memory, count lines, etc etc. I can't use Filestream.Setlength because that needs readwrite access and the log will be opened by another application. And it has to be fast. However, the line ends in a cr/lf meaning the last line is actually empty. Been struggling with this all day, and its hurting my head! Not good on a Friday!
I have a function that can read the last line but can't get it to go one line up. I can get it to read characters from the end of the line, but that's not much of a help with a variable length line!
Maybe fs SeekOrigin would work as it could run backwards looking at an example from MSDN - need to get the data before the last cr/lf and end at the next one... hmmm... problem is that that example also writes the text backwards as well.
I'm monitoring the log for particular entries for issues that are causing us grief at the moment.
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Feb 25, 2009
the best method to read a huge file? I'm guessing its with "stream"?It's like a 200mb file.I need to read each line and do something if the line contains a search string.
Code:Imports System.IO
Public Class Form1 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim strFile As String = "c:
[code].....
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Aug 15, 2011
I have a data file which I am de-compressing and then reading line by line.This includes data which is then read by my function which is split into sperate bits then inserted into a database.My reader is currently taking ages. (largest file being 1.8GB)I am using:
Code:
' File exists, read file.
Dim objReader As New System.IO.StreamReader(fileName)[code]....
Is there a quicker way to do this? And possibly a progress bar to show how far it is through the file?
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Oct 14, 2011
what i need to do is open a txt file, read line by line, decode each line into an array and display. Now all works ok apart from one line.
sTextLine = objReader.ReadLine() <-- Value of string cannot be converted.
full code here
-------------
Dim objReader As New System.IO.StreamReader(sOpenFile.Text)
Dim sTextLine As New ArrayList()
Dim sText As String = ""
Dim i As Integer = 0
[code]....
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Apr 4, 2012
The file is a UTF8 text files.
Each characters has varying number of bytes and each line has varying number of characters.
Does vb.net has table of line numbers to byte location function or something like that?
Also after that how to read that?
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Jun 26, 2009
Is there an easy way to insert a line into the very beginning of a large file?I want to insert an XML header line into XML files that my program processes (These files can be very large, so reading it via bitstream and writing it out is not a good option).
File.AppendText makes it very easy to append lines to the end of a file, but I don't see anything for inserting text.I wonder how does say Access work in processing say a 50 meg access database file? There must be a similar process where you can insert data anywhere inside a large file.
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Mar 16, 2010
I am trying to read this XML document.
An excerpt:
<datafile xmlns:xs="[URL]" xmlns:xsi="[URL]" xsi:noNamespaceSchemaLocation="wiitdb.xsd">
<WiiTDB version="20100217113738" games="2368"/>
<game name=" Wanted: 50 Wacky Jobs (DEMO) (USA) (EN)">
<id>DHKE18</id><type/>
<region>NTSC-U</region>
[Code] .....
It just skips the "While iter.MoveNext" part of the code. I tries it with a simple XML file, and it works fine.
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Mar 11, 2010
I have a txt file that I need to read into a listview, but I need to read from a specific line in that file. Below is a sample of the txt file to read,
6400,3200,2,95.5,84,76.6,0
1,2,-20,15,0,0,0,"NO",0,0
TOTAL GPM= 6400 HWT= 95.5 CWT= 84.0 IWBT= 76.6 ALTITUDE= 0
CODE]...
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Mar 17, 2010
I'm trying to read a file line by line into an array but It skips the item at index:3 I have it msgboxing just to make sure and it wont even touch it.
Dim Btn As Button = DirectCast(sender, Button)
Dim path As String = Application.StartupPath & "Libraries" & Btn.Text.Replace(" ", "_") & ".ipt"
Dim i As Integer = 0
Dim lines As String() = IO.File.ReadAllLines(path)
[code]....
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Aug 30, 2010
I like search a file TXT with this contains:
Name "Paul"
Age "11"
City "Chicago"
my question is: Its possible get a string "Name" and give me the value "Paul"? I have this function for get strings:
[code]...
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Feb 20, 2012
Why can I only see the first line split in the listboxes repeated 4 times? I can not see all the lines of the Dictionary.[code]...
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Jun 22, 2009
I have code that reads the whole file, not line by line.
Here is the code:
FileOpen(1, filename, OpenMode.Input)
Do While Not EOF(1)
datatodisplay = LineInput(1)
Loop
FileClose(1)
I would like to know how I can read the file line by line and then add all results into an array list.
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Dec 26, 2009
I need to read a xls/xlsx/ods/txt file line by line,to get a column name of file .how to read a file line by line in vb.net?
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Sep 19, 2010
Ok, I saw this code on the net
Dim sFileName As String
Dim srFileReader As System.IO.StreamReader
Dim sInputLine As String
sFileName = "D:UsersArbenDesktopSerieA.txt"
srFileReader = System.IO.File.OpenText(sFileName)
[Code]...
under the code I pasted at the top, but I get the text on line1 in all labels, like all labels become 1, while the text should be 1, 2, 3 and so on. So anyone can help me do that, each label gets the value of the next line in the txt file
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Oct 24, 2009
I have created a program that saves the co-ordinates of the users mouse and saves it to a text file to be used as an auto clicker.
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Mar 25, 2011
I have a text file like below;
606;16
101 GAZ MET.MED. - VIC.BRANESTI 2011-01-11T11:00:00
102 BRASOV - TARGU MURES 2011-01-11T10:30:00
[code].....
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May 4, 2009
I am trying to read a PDF file line by line using PDFBox.This is the first time I have ever attempted to do this with a PDF so I am not sure what I was expecting but I thought I would end up with some "mark up", which I could use to parse the lines I was looking for out of the file.
Anyway it didn't work out the way I had planned and I am not sure if that is because I am using the wrong tool or not using the right tool correctly.I managed to extract the text but I didn't really see any mark up that would be usefull to parse the file. Does anybody have any experiece with extracting test from PDFs. What tool(s) do you recomend?
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Mar 29, 2012
I am quite new in VB NET, after VB. and unfortuantely I had to copy paste and merge the code fragments from some tutorials.
I have a folder including 200 eng files which can be opened by notepad. And each file has around 4000 row; with 60 field seperated by coma. I need to read specific row-field value at each files.
Now what I can is:
a) reading individual txt files and find specific value
b) listing all of the files in the folder
c) I can merge (a) and (b) and read all the files automatically, but since ram is continuously increasing, and at one point (sometimes 163, sometimes 169, or 170. files or something) it gives an error as "System.OutOfMemoryException". My ram is 4 GB and when I get this error the ram is increasing to more than 3 GB.
1- Could it be happen because of being eng files instead of regular txt files?[code]...
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Dec 14, 2009
how can I read data in a file line by line..for eg in my project I have to store movie information in a file and every movie's info has to be in one line..this is my code for file
Private Sub btn_Read(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
sw.Close()
fs.Close()
fs = New FileStream(filetxt.Text, FileMode.Open, FileAccess.Read)
[code]....
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Aug 21, 2011
how to read a simple text file line by line like when you're writing to a file with System.IO.StreamWriter where you write to the file line by line.
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Apr 11, 2012
if i want to read from txt file called "students" line by line and after reading each line, I want to split the information To make sure a user or not
[Code]...
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Dec 9, 2009
I'm using Visual Basic express 2008.The application I am working on is the first major project I have ever undertook with visual basics. The application is a launcher for a private server for world of warcraft.I have a menu bar that pulls the file path of the wow.exe and puts it in a hidden textbox, I then have another option that saves this text to c:wowexe.txt. All of this works GREAT!
How can I read the .txt file to end and return the information stored in the .txt file to this line of code.
Dim RetVal
RetVal = Shell("This is where I need the data from the .txt file to be seen", 1)
If your wondering why I don't just type in the path of the .exe, it's simple, not everyone installs World of Warcraft on the C drive.
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May 21, 2009
in my text file i have two part. Called bottom and top. So i need to read the Top part first then and match the line with bottom part. Its like this
[Code]...
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Oct 31, 2010
Basically, I am trying to create an FTP shoutbox system. I have a sub which adds text to an FTP text file. The most recent post is on the top, and the descending items get older in age. I tested this sub and it works fine. However, I get an error when trying to do my 'RefreshShoutbox' sub.
Dim x As String
Form1.ListBox3.Items.Clear()
[code]....
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Oct 6, 2011
I need to be able to read the last line of a text log file - a bit like the Unix 'tail -f'. I'm using FileSystemWatcher which works well. There's more to it than that and more complexity to the app, and I have everything working fine except this bit. I've tried googling for it but I can't get any of the examples work properly.
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Jan 16, 2011
how to read text from a listbox line by line and put current line in a label?
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Feb 23, 2011
I have a txt file I' m trying to read a line and add it to the array list, I' m identying the begining of the new line with B and N charecters in the 11 and 12 th positions respectively. Now the problem is that few keys are getting dropped the structure of the file is
10000BN test 1 test2
10000S0000 test3 test 4// these are getting dropped because they are on a new line
10000S 0000 test5
so how do I add these two lines to the record
[Code]....
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Sep 8, 2011
I have this to read a random line from a .txt file[[code]....
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Jan 11, 2010
In VB.net I'm trying to read in a specific line from a file. An example of the line in the txt file is:
[PATH] = "/this/directory/run.exe"
how to open the file for reading and writing in VB, but I need to parse out the path in the "" (quotation marks).
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Dec 15, 2008
I have a text file that has a list of certain values and I need to read each one back to the correct variable.
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