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+---- Thread: [.NET] Cycle through Text Files For Specific Line? (/showthread.php?tid=5726998)
Cycle through Text Files For Specific Line? - Haters Ganna Hate - Sep 28, 2017
So I have a very large 10GB text file that I split into 130 80MB text files. I need to cycle through all of them until I find a certain name.
I know by looking at one text file, I can use this:
Code
Using reader As New StreamReader("Test.txt")
While Not reader.EndOfStream
Dim line As String = reader.ReadLine()
If line.Contains("Banana") Then
TextBox1.Text = line
Exit While
End If
End While
End UsingBut I need it to go to the next text file if the first text file does not have it. Luckily, the text files all start with the name "split" and their names are like:
- split1
- split2
- split3
I just need a loop or something that checks every single "split" text file for a keyword until it found it.
Got a code example?
* - DBots - Sep 28, 2017
Directory.GetFiles() has an option to set a filter.
Here's what I did:
![[Image: 4c53d55514fb0d563cf20969878fca34.png]](https://i.gyazo.com/4c53d55514fb0d563cf20969878fca34.png)
* - Haters Ganna Hate - Sep 29, 2017
(Sep 28, 2017 10:14 PM)DBots Wrote: Directory.GetFiles() has an option to set a filter.
Here's what I did:
Does not seem to work. Here is my Form:
![[Image: VuJL3ScH0A.png]](https://anonimage.net/db/full/VuJL3ScH0A.png)
And here is my code: https://pastebin.com/w94pEey4
I have two files called "split1" which contains:
Quote:John Smith
John Rocke
Jacob Means
Rachial Sam
And "split2" which contains:
Quote:Naing Man
Wu Sam Lem
Kemo Kam
Haha Rob
But when I search up the term "Haha Rob", it says it finds it in both split1 and split2 repeatedly. Im a little tired now and its dark so maybe I am not seeing something?
* - DBots - Sep 29, 2017
after you .ReadLine, you need to compare it to the target string like
If sLine.Equals(sTargetString) Then..
So yeah it seems you overlooked that part which you actually had something like that in your original code.
* - Owl - Sep 29, 2017
Code
Dim target As String = "Haha Rob"
For Each file In Directory.GetFiles("path", "split*.txt")
Using sr As New StreamReader(file)
While Not sr.EndOfStream
Dim line As String = sr.ReadLine()
If line.Contains(target) Then
Console.WriteLine(line)
Exit For
End If
End While
End Using
NextWorks fine.
* - DBots - Sep 29, 2017
OrKa got it! But man you should have let him try a little more he almost had it lol.
* - joey karate - Sep 29, 2017
open up notepad++
http://prntscr.com/grabni
* - dicktembe - Sep 30, 2017
I cycle through text files like this:
Code
If IO.File.Exists(datafilepath) Then
Dim datafile As List(Of String) = IO.File.ReadAllLines(datafilepath).ToList()
For i = 0 To datafile.Count - 1
If datafile(i).Contains("SEARCH STRING HERE") Then
'do something here
End If
Next
End IfExample, here I open a file and get to a certain line that contains 'MouseSensitiveList=', I then get values of certain settings and replace them because I know they are 8 chars long. However you can do anything you like:
Code
If IO.File.Exists(configpath) Then
Dim config As List(Of String) = IO.File.ReadAllLines(configpath).ToList()
For i = 0 To config.Count - 1
If config(i).Contains("MouseSensitiveList=") Then
For j = 0 To 8
Dim indexpos As Integer
If j = 0 Then
indexpos = config(i).IndexOf("LastConvertedMouseSensitivity=") + 30
Else
indexpos = config(i).IndexOf("LastConvertedMouseSensitivity=", indexpos) + 30
End If
If j < 3 Then
config(i) = config(i).Remove(indexpos, 8).Insert(indexpos, txtPUBG.Text)
ElseIf j >= 3 And j < 8 Then
config(i) = config(i).Remove(indexpos, 8).Insert(indexpos, txtPUBGSCOPED.Text)
End If
Next
IO.File.WriteAllLines(configpath, config)
MsgBox("Config file written! (I hope, hehe xd)")
End If
Next
End If* - Ninja - Oct 1, 2017
(Sep 30, 2017 08:38 AM)dicktembe Wrote: - SNIP -
You read all contents of the text file at once into the program. This is not a good solution at all for handling large text files like OP is (130x 80MB).
@OP; if you need random access I suggest using the MemoryMappedFile class, so you can get complete, and random access to a file without the need for seeking. If you don't, then a StreamReader and reading line by line like you already have is fine.
RE: Cycle through Text Files For Specific Line? - Cairns - Nov 7, 2017
If you're reading a 10GB file that wont go too smoothly with any of those methods.
I suggest you read x amount of lines (5000 lines for example) and append it to a stringbuilder, then check the stringbuilder.tostring if it contains the line text. If not, then continue running the cycle/loop until done. Do not read a 10GB file into memory at once and continuously check EACH line because it's gonna be a memory killer and its gonna take forever.
RE: Cycle through Text Files For Specific Line? - gigajew - Nov 7, 2017
Here's how I do it
Code
using (var reader = new StreamReader("file.txt")) {
while (sr.Peek() >= 0) {
var line = sr.ReadLine();
Console.WriteLine(line); // do whatever you want with the line
}
}RE: Cycle through Text Files For Specific Line? - 0xDEAD10CC - Nov 7, 2017
None of the above solutions is going to work very fast without dealing with mapping files into memory and reading things that way. When you start dealing with GB's the naive and most obvious approaches are the worst. That class posted by Ninja is essentially a wrapper around native functions like MapViewOfFile(), which is what I personally use to read large files > 1GB in fractions of the time it takes using normal (portable) methods. (mmap() for those on Linux.)
That class makes it much easier than using the functions directly though because otherwise you'll be calculating pointer offsets, allocating to match system granularity, among other things.