How To Get A Line From A Large File
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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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 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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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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Feb 3, 2011
I'm fiddling around with trying to make a sort of map/world. I'm using 16 x 16 pictureboxes named PictureBox1, PictureBox2, etcThe issue is that when I put the images into all the pictureboxes, I have to have a line for each picturebox (so say I have 100 boxes, I have 100 lines).The only difference in each line is the picturebox number, the rest is identical. I'm basically telling it to set that picturebox's image based on the number that a variable I've created has stored.I've got a game idea, and I'm just trying to figure out how to do the map. I want it to work like the old school RPG games like Dragon Warrior, or the more recent Dwarf Fortress. I'm still not sure if I want to use graphics or letters. At this point, I'm just trying to figure out how I can create the main screen where the user moves around. This is what I've come up with, as it works with what I know. I'm pretty new to this, although I've messed around with VB6 a lot.
Dim tile(30) As Integer
Dim tilelocation(3) As String
Dim x As Integer
[code]....
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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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Dec 1, 2011
How would i go about reading a file Line by Line that within that line The values are delimited by " Example of the data:
"bob" "cat" "1243"
"steve" dog" "6789"
I've started this with this code but not sure how to go about the next stage:
Using MyReader As New _
Microsoft.VisualBasic.FileIO.TextFieldParser(My.Application.Info.DirectoryPath & "Records28112011.jd")
MyReader.TextFieldType = FileIO.FieldType.Delimited
[code]....
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Jun 4, 2012
I am creating a VB application in Visual Studio 2010 that installs some SQL stored procedures. These stored procedures are encrypted otherwise I would just supply my clients with .sql files to create the stored procedures.
The install script that creates the stored procedure is 1500 lines in length and has been formatted in the way VS 2010 requires multi-line literals to be in:
"First Line" & _
"Second Line" & _
"etc..."
[Code]....
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Jun 23, 2011
I'm reading a text file with StreamReader, line by line. If a condition is met, then I do an operation and then start reading the file again from the first line. I realize I could close and then re-open the file, but surely this would be very slow.
I could do this easily in VB6, but pulling my hair out trying to do this in vB.net. It seems that 'Seek' is the function to use, but it doesn't work.
I've seen other examples, where it works, but you must open it a different way -- with a file number.
Imports System.IO
Dim I as Integer
Dim LineText as String
[Code].....
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Jun 9, 2011
I want to write a program to do Markov chain, but my states are quite large. First of all I calculate all the transition probabilities and revenues for all states(1381860 total states), and store in a multidimensional array. Public RevArr(0 To 9, 0 To 750, 0 To 282) As Long
After that the iteration of markov chain should use these as inputs to calculate the steady-state probabilities. But when I try to run the main code I got this error.Exception of type 'System.OutOfMemoryException' was thrown.
The following is the declaration of second array I add just another dimension for storing all the iterations, but I get this error. Dim stateprob(IT + 1, 0 To 9, 0 To 750, 0 To 282) As single
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Aug 26, 2011
this code takes about 30 mins and high cpu usage, what is the problem
Do
strLine = objReader.ReadLine()
If strLine Is Nothing Then
[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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Apr 1, 2011
I'm having trouble with reading a .txt file line by line, converting it into a string, then putting it into a listbox. When I execute I get an error saying "IndexOutOfRangeException was unhandled" Here is my
[Code]...
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Jun 29, 2009
i would like to store contents from a text file line by line to arrays before copying them to another text file. what i have is currently like this:
[Code]...
Currently I'm only able to store the whole content into one variable, would like to store the content line by line in arrays.
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Aug 26, 2011
this code takes about 60 mins and high cpu usage for a text file of 90,000 lines, what is the problem..[code]
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Jan 20, 2010
show me a simple code for downloading a file from internet with a URL,Line by Line with streamreader?
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Sep 20, 2010
I'm trying to read an .rtf file one line at a time but I'm clearly missing something!The file contains 3 lines and I want each line to end-up in a different RichTextBox, so:
Open File
RichTextBox1 = 1st Line in File
RichTextBox2 = 2nd Line in File
RichTextBox3 = 3rd Line in File
Close File
What am I not understanding? I've tried using LoadFile to load the whole file into another RichTextBox first as I got the impression that RichTextBoxes are indexed - but what I got was strings not .rtf format. I've also looked to see if there's an equivalent of the text-centric ".ReadLine" and nothing seems to fit the bill.
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Jul 21, 2011
I my old vb6 i use the tipical Open "c:somefile.vbw" For Output As #1 ecc...and loop into txt file line by line....Now i'am new in vb2010i need a little project in vb2010
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May 14, 2009
I have to create a new program that reads to Text files. These text files are in the form of a report (with column headings). The purpose is to compare each record line by line to see if their have been any changes made. The record is based on an Account#. Over time these files will be considerably large. What is the best way to do compare records from each file. I'm thinking loading each file into an array and processing them that way.
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Mar 5, 2009
I'm making a program which has 7 textboxes. I intend the program to be used for classes in school, so the text would be like 2D Art, Geology etc... whatever your classes are. I have figured out how to use the streamwriter to take the text in the textboxes and write them to a .txt file however, my issue is with loading the text from the .txt file back into the textboxes. I did figure out how to write it so that all the text in the .txt file is loaded back into textbox1 but I have 7 textboxes... Here's the coding for the Load button:
Private Sub Button46_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button46.Click
Dim MainWindowLog As String = "V:Users(O.o)~(--_--)~(o.O)DocumentsVisual Studio
[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 11, 2011
Basically, I'm creating an application which takes a list of words in .txt format, such like this:
Abc
Def
Ghi
Jkl
mno
What I want to be able to do is modify the words, one by one, so that I end with
Abc1
Def1
Ghi1
Jkl1
mno1
or whatever the user wants.
I created this app in C++ to get the logic, since I am more confident with that
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Mar 19, 2012
I must use streamreader to read text file line by line into array.
Here's what I've got.
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim numbers() As Double = New StreamReader(txtfile.Text)
Dim numbersarray() As Double
[Code].....
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Apr 8, 2010
I just joined this forum as I've been looking for a nice and serious VB forum for a long time
I'm having troubles making a program to search a text file line by line for a specific string.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim objReader As New System.IO.StreamReader("C: est.txt")
[Code]...
as you can see in the code its supposed to read a text file and if the line contains the same string as in the textbox then its gonna make a messagebox.
now the problem, if the line does not contain the specific string but the next or any line other line does, then it should automatically read the next line on "Else" and that's where I'm lost
for a "Readnextline" command or something like that?
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Sep 26, 2009
I have a list of random numbers in my text file.I read it like this.
Dim FILE_NAME As String = "C: est.txt"
Dim TextLine As String
If System.IO.File.Exists(FILE_NAME) = True Then
[code]....
How can I separate that in to 2 listbox?In my ListBox1 I want add lines with starting number like this ( 0905, 0906, 0915, 0916, 0917, 0926, 0927 ) And in my ListBox2 is with numbers start with this ( 0909, 0910, 0912, 0918, 0919, 0920, 0921, 0928, 0929 )How can I compare lines by multiple choices like that?
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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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