It's been a long time since I've programmed. I'm writing a form in VB.NET, and using StreamReader to read a text file and populate an 2D array. Here is the text file:
あかさたなはまやらわん
いきしちにひみ り
うくすつぬふむゆる
えけせてねへめ れ
おこそとのほもよろを
And here is the loop, which is within the Load event.
Dim Line As String
Dim Row As Integer = 0
Using sReader As New IO.StreamReader("KanaTable.txt")
Do
Line = sReader.ReadLine
For i = 0 To Line.Length - 1
KanaTable(Row, i) = Line(i)
Next
Row += 1
Loop Until sReader.EndOfStream
End Using
The problem is, once the i in the For Loop reaches 10, it completes the loop and skips the other lines, even when I have a breakpoint. Can you let me know what's probably going on here?
I've figured out the problem, it was very simple. The array declaration for KanaTable:
Dim KanaTable(4, 9) As Char
should have been
Dim KanaTable(4, 10) As Char
Because there was one less space in the array than there should have been, the debugger must have been throwing an IndexOutOfRange which I couldn't see, because, stupid Windows bug (thanks to Bradley Uffner for pointing out this bug.)
If you can use an array of arrays or a list of arrays (List(Of Char())), you can get this down to a single line of code:
Dim KanaTable()() As Char = IO.File.ReadLines("KanaTable.txt").Select(Function(line) line.ToCharArray()).ToArray()
If that's too complicated for you, we can at least simplify the existing code:
Dim KanaTable As New List(Of Char())
Dim Line As String
Using sReader As New IO.StreamReader("KanaTable.txt")
Line = sReader.ReadLine()
While Line IsNot Nothing
KanaTable.Add(Line.ToCharArray())
Line = sReader.ReadLine()
End While
End Using
I can't see an error immediately, but you could try to adapt your code to this:
Using reader As New IO.StreamReader("KanaTable.txt")
Do
line= reader.ReadLine()
If line = Nothing Then
Exit Do
End If
For i = 0 To Line.Length - 1
KanaTable(Row, i) = Line(i)
Next
Row += 1
Loop
End Using
Related
Sorry for the terrible wording on my last question, I was half asleep and it was midnight. This time I'll try to be more clear.
I'm currently writing some code for a mini barcode scanner and stock manager program. I've got the input and everything sorted out, but there is a problem with my arrays.
I'm currently trying to extract the contents of the stock file and sort them out into product tables.
This is my current code for getting the data:
Using fs As StreamReader = New StreamReader("The File Path (Is private)")
Dim line As String = "ERROR"
line = fs.ReadLine()
While line <> Nothing
Dim pos As Integer = 0
Dim split(3) As String
pos = products.Length
split = line.Split("|")
productCodes(productCodes.Length) = split(0)
products(products.Length, 0) = split(1)
products(products.Length, 1) = split(2)
products(products.Length, 2) = split(3)
line = fs.ReadLine()
End While
End Using
I have made sure that the file path does, in fact, go to the file. I have looked through debug to find that all the data is going through into my "split" table. The error throws as soon as I start trying to transfer the data.
This is where I declare the two tables being used:
Dim productCodes() As String = {}
Dim products(,) As Object = {}
Can somebody please explain why this is happening?
Thanks in advance
~Hydro
By declaring the arrays like you did:
Dim productCodes() As String = {}
Dim products(,) As Object = {}
You are assigning size 0 to all your arrays, so during your loop, it will eventually try to access a position that haven't been previously declared to the compiler. It is the same as declaring an array of size 10 Dim MyArray(10) and try to access the position 11 MyArray(11) = something.
You should either declare it with a proper size, or redim it during execution time:
Dim productCodes(10) As String
or
Dim productCodes() As String
Dim Products(,) As String
Dim Position as integer = 0
'code here
While line <> Nothing
Redim Preserve productCodes(Position)
Redim Preserve products(2,Position)
Dim split(3) As String
pos = products.Length
split = line.Split("|")
productCodes(Position) = split(0)
products(0,Position) = split(1)
products(1,Position) = split(2)
products(2,Position) = split(3)
line = fs.ReadLine()
Position+=1
End While
I have a Streamreader which is trowing an error after checking every line in Daycounts.txt. It is not a stable txt file. String lines in it are not stable. Count of lines increasing or decresing constantly. Thats why I am using a range 0 to 167. But
Here is the content of Daycounts.txt: Daycounts
Dim HourSum as integer
Private Sub Change()
Dim R As IO.StreamReader
R = New IO.StreamReader("Daycounts.txt")
Dim sum As Integer = 0
For p = 0 To 167
Dim a As String = R.ReadLine
If a.Substring(0, 2) <> "G." Then
sum += a.Substring(a.Length - 2, 2)
Else
End If
Next
HourSum = sum
R.Close()
End Sub
If you don't know how many lines are present in your text file then you could use the method File.ReadAllLines to load all lines in memory and then apply your logic
Dim HourSum As Integer
Private Sub Change()
Dim lines = File.ReadAllLines("Daycounts.txt")
Dim sum As Integer = 0
For Each line In lines
If line.Substring(0, 2) <> "G." Then
sum += Convert.ToInt32(line.Substring(line.Length - 2, 2))
Else
....
End If
Next
HourSum = sum
End Sub
This is somewhat inefficient because you loop over the lines two times (one to read them in, and one to apply your logic) but with a small set of lines this should be not a big problem
However, you could also use File.ReadLines that start the enumeration of your lines without loading them all in memory. According to this question, ReadLines locks writes your file until the end of your read loop, so, perhaps this could be a better option for you only if you don't have something external to your code writing concurrently to the file.
Dim HourSum As Integer
Private Sub Change()
Dim sum As Integer = 0
For Each line In File.ReadLines("Daycounts.txt")
If line.Substring(0, 2) <> "G." Then
sum += Convert.ToInt32(line.Substring(line.Length - 2, 2))
Else
....
End If
Next
HourSum = sum
End Sub
By the way, notice that I have added a conversion to an integer against the loaded line. In your code, the sum operation is applied directly on the string. This could work only if you have Option Strict set to Off for your project. This setting is a very bad practice maintained for VB6 compatibility and should be changed to Option Strict On for new VB.NET projects
I have this code but it have errors , what should i do ?
Dim lines As New List(Of String)
lines = RichTextBox1.Lines.ToList
'Dim FilterText = "#"
For i As Integer = lines.Count - 1 To 0 Step -1
'If (lines(i).Contains(FilterText)) Then
RichTextBox1.Lines(i) = RichTextBox1.Lines(i).Replace("#", "#sometext")
'End If
Next
RichTextBox1.Lines = lines.ToArray
Update: while the following "works" it does only modify the array which was returned from the Lines-property. If you change that array you don't change the text of the TextBox. So you need to re-assign the whole array to the Lines-property if you want to change the text(as shown below). So i keep the first part of my answer only because it fixes the syntax not the real issue.
It's not
RichTextBox1.Lines(i).Replace = "#sometext"
but
RichTextBox1.Lines(i) = "#sometext"
You can loop the Lines forward, the reverse loop is not needed here.
Maybe you want to replace all "#" with "#sometext" instead:
RichTextBox1.Lines(i) = RichTextBox1.Lines(i).Replace("#","#sometext")
So here the full code necessary (since it still seems to be a problem):
Dim newLines As New List(Of String)
For i As Integer = 0 To RichTextBox1.Lines.Length - 1
newLines.Add(RichTextBox1.Lines(i).Replace("#", "#sometext"))
Next
RichTextBox1.Lines = newLines.ToArray()
But maybe you could even use:
RichTextBox1.Text = RichTextBox1.Text.Replace("#","#sometext")`
because if we have # abcd this code change it to # sometextabcd ! I
Want a code to replace for example line 1 completely to # sometext
Please provide all relevant informations in the first place next time:
Dim newLines As New List(Of String)
For Each line As String In RichTextBox1.Lines
Dim newLine = If(line.Contains("#"), "#sometext", line)
newLines.Add(newLine)
Next
RichTextBox1.Lines = newLines.ToArray()
I'm trying to rid a text file of currupt data. I parse the file and if I find a bad character, I replace it with a space. My problem is that the space is not overwriting the bad character. Instead, the space is written on line 10 position 27. What's going on here?
I've been stuck on this seemingly simple problem for half a day. Thanks.
Sub replaceChars(fname As String)
Dim fs As New FileStream(fname, FileMode.Open, FileAccess.ReadWrite)
Dim r As New StreamReader(fs)
Dim w As New StreamWriter(fs)
Dim iChar As Integer = 0
Do Until r.Peek() = -1
iChar = r.Read()
If iChar < 32 Or iChar > 126 Then
If iChar = 13 Or iChar = 10 Then 'cr/lf, continue.
Continue Do
Else 'found a bad char. replace it.
w.Write(Chr(32))
w.Flush()
fs.Flush()
End If
Else
Continue Do
End If
Loop
w.Close()
fs.Close()
End Sub
I really dont like the idea that you share a filestream for a reader and a writter, since I have had lots of 'unreasonable' problems because of that.
I've leanred that when using a Idiposable objects use 'Using' Statement wich waranties that proceses is finished, and you are not getting wired errors.
try this, maybe it helps and it is always better to do it this way.
Using Statement
I would ask if you could give me some alternatives in my problems.
basically I'm reading a .txt log file averaging to 8 million lines. Around 600megs of pure raw txt file.
I'm currently using streamreader to do 2 passes on those 8 million lines doing sorting and filtering important parts in the log file, but to do so, My computer is taking ~50sec to do 1 complete run.
One way that I can optimize this is to make the first pass to start reading at the end because the most important data is located approximately at the final 200k line(s) . Unfortunately, I searched and streamreader can't do this. Any ideas to do this?
Some general restriction
# of lines varies
size of file varies
location of important data varies but approx at the final 200k line
Here's the loop code for the first pass of the log file just to give you an idea
Do Until sr.EndOfStream = True 'Read whole File
Dim streambuff As String = sr.ReadLine 'Array to Store CombatLogNames
Dim CombatLogNames() As String
Dim searcher As String
If streambuff.Contains("CombatLogNames flags:0x1") Then 'Keyword to Filter CombatLogNames Packets in the .txt
Dim check As String = streambuff 'Duplicate of the Line being read
Dim index1 As Char = check.Substring(check.IndexOf("(") + 1) '
Dim index2 As Char = check.Substring(check.IndexOf("(") + 2) 'Used to bypass the first CombatLogNames packet that contain only 1 entry
If (check.IndexOf("(") <> -1 And index1 <> "" And index2 <> " ") Then 'Stricter Filters for CombatLogNames
Dim endCLN As Integer = 0 'Signifies the end of CombatLogNames Packet
Dim x As Integer = 0 'Counter for array
While (endCLN = 0 And streambuff <> "---- CNETMsg_Tick") 'Loops until the end keyword for CombatLogNames is seen
streambuff = sr.ReadLine 'Reads a new line to flush out "CombatLogNames flags:0x1" which is unneeded
If ((streambuff.Contains("---- CNETMsg_Tick") = True) Or (streambuff.Contains("ResponseKeys flags:0x0 ") = True)) Then
endCLN = 1 'Value change to determine end of CombatLogName packet
Else
ReDim Preserve CombatLogNames(x) 'Resizes the array while preserving the values
searcher = streambuff.Trim.Remove(streambuff.IndexOf("(") - 5).Remove(0, _
streambuff.Trim.Remove(streambuff.IndexOf("(")).IndexOf("'")) 'Additional filtering to get only valuable data
CombatLogNames(x) = search(searcher)
x += 1 '+1 to Array counter
End If
End While
Else
'MsgBox("Something went wrong, Flame the coder of this program!!") 'Bug Testing code that is disabled
End If
Else
End If
If (sr.EndOfStream = True) Then
ReDim GlobalArr(CombatLogNames.Length - 1) 'Resizing the Global array to prime it for copying data
Array.Copy(CombatLogNames, GlobalArr, CombatLogNames.Length) 'Just copying the array to make it global
End If
Loop
You CAN set the BaseStream to the desired reading position, you just cant set it to a specfic LINE (because counting lines requires to read the complete file)
Using sw As New StreamWriter("foo.txt", False, System.Text.Encoding.ASCII)
For i = 1 To 100
sw.WriteLine("the quick brown fox jumps ovr the lazy dog")
Next
End Using
Using sr As New StreamReader("foo.txt", System.Text.Encoding.ASCII)
sr.BaseStream.Seek(-100, SeekOrigin.End)
Dim garbage = sr.ReadLine ' can not use, because very likely not a COMPLETE line
While Not sr.EndOfStream
Dim line = sr.ReadLine
Console.WriteLine(line)
End While
End Using
For any later read attempt on the same file, you could simply save the final position (of the basestream) and on the next read to advance to that position before you start reading lines.
What worked for me was skipping first 4M lines (just a simple if counter > 4M surrounding everything inside the loop), and then adding background workers that did the filtering, and if important added the line to an array, while main thread continued reading the lines. This saved about third of the time at the end of a day.