I'm a bit of a newbie so any advice would be great. I have a program
that opens a CSV, and then saves it as a csv with a different name. there will be a set of rules to change fields but haven't got that far yet.
when I run this on a small csv file (about 4 columns and rows) it works fine, but with a larger file, it fails with the error above. i'm sure its something daft but I I'm at a loss.
Thanks,
Dean
Dim FileName = tbOpen.Text
Dim fileout = tbSave.Text
Dim lines = File.ReadAllLines(FileName)
Dim output As New List(Of String)
For Each line In lines
Dim fields = line.Split(","c)
If fields(1) = "" Then 'This is where the error is triggered
fields(1) = "Norman"
End If
If fields(3) = "" Then
fields(3) = "Blue Leather"
End If
If fields(4) = "" Then
fields(3) = "Interlined"
End If
output.Add(String.Join(","c, fields))
Next
File.WriteAllLines(fileout, output)
Try
Dim a As String = My.Computer.FileSystem.ReadAllText(tbSave.Text)
Dim b As String() = a.Split(vbNewLine)
ListBox2.Items.AddRange(b)
Catch ex As Exception
MsgBox("error")
End Try
Keep in mind that arrays start a index 0. VB is notorious for stretching this concept. Normally, when you declare an array with 10 elements the indexes would be from 0 - 9. With VB, on the other hand, the indexes will be from 0 - 10 which will actually give you 11 elements.
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 need to do search and replace across 2 lines of a large ascii text file, where this may occur n times (n>1000) in random places. A text file looks like this:
....
StringVariable='
my contents'
.....
and I want it to read:
....
StringVariable='my contents'
....
For small files, I use AllText, which works fine for small files:
My.Computer.FileSystem.WriteAllText(MyInputFile, My.Computer.FileSystem.ReadAllText(MyOutputFile).Replace("='" & vbCrLf, "='"), False)
For large ones, AllText crashes with out of memory error. I see posts to use ReadLine and WriteLine, and how to test strings for characters, but I am missing how to combine multiple lines 'n' times without losing my place in the file. I guess I could split the large file into many small files carefully to allow use of AllText, and then recombine, but that seems crude. Is there a better way?
I see how to fix the case listed above, but I have other cases (e.g, 2 CR's after a specific string) and struggling to resolve for flexible case where you want to replace a multi-line string with a variable length multi-line string.
Here is the code I used for the initial case above:
Private Sub RemoveCRBefore(ByVal Infile As String, ByVal Outfile As String, ByVal LookedFor As String)
Dim Line0 As String = ""
Dim LinedUp As String = ""
Dim LookLong As Integer = LookedFor.Length
Dim FirstLine As Boolean = True
Using sr As StreamReader = New StreamReader(Infile)
Using sw = System.IO.File.CreateText(Outfile)
Dim Line1 As String = sr.ReadLine
Do While (Not Line1 Is Nothing)
If Line1.Length >= LookLong Then
If LookedFor = Line1.Substring(0, LookLong) And Not FirstLine Then
LinedUp = Line0.Replace(vbCrLf, "") & Line1
Line0 = LinedUp
FirstLine = True
Else
If FirstLine = False Then sw.WriteLine(Line0)
Line0 = Line1
End If
Else
sw.WriteLine(Line0)
Line0 = Line1
End If
Line1 = sr.ReadLine
FirstLine = False
Loop
sw.WriteLine(Line0)
End Using
End Using
End Sub
Hi i am new to VB and in the process of learning. This error occur sometimes and doesn't occur sometimes which i find it weird.
I receive the error Index was outside the bounds of the array, that points to Button30.Text = Split(newestversion, vbCrLf)(**1**)
My motive is to read line by line from a online hosted text file.
For example,
label1.text = line 1 of the text file
label2.text = line 2 of the text file
This is very much what i want.
Here is my current code (EDITED):
Dim request As System.Net.HttpWebRequest = System.Net.HttpWebRequest.Create("direct link to my online txt file")
Dim response As System.Net.HttpWebResponse = request.GetResponse
Dim sr As System.IO.StreamReader = New System.IO.StreamReader(response.GetResponseStream)
Dim stringReader As String
stringReader = sr.ReadLine()
Button10.Text = stringReader
Dim newestversion As String = sr.ReadToEnd
Dim currentversion As String = Application.ProductVersion
Dim part() As String = Split(newestversion, vbCrLf)
If part.Length < 10 Then
' not enough items in the array. You could also throw and exception or do some other stuff here
Label10.Text = "beta"
Exit Sub
End If
'updates new episode numbers on buttons
Button20.Text = part(0)
Button30.Text = part(1)
Button40.Text = part(2)
Button50.Text = part(3)
Button60.Text = part(4)
Button70.Text = part(5)
Button80.Text = part(6)
Button90.Text = part(7)
Button100.Text = part(8)
Button110.Text = part(9)
End If
Thank You!!
You split your String for line breaks. This gives you an array, having one entry for each line in the String. However, you do not check if this array holds the amount of items you expect. You could do:
Dim newestversion As String = sr.ReadToEnd
Dim currentversion As String = Application.ProductVersion
Dim part() As String = Split(newestversion, vbCrLf)
If part.Length < 10 Then
' not enough items in the array. You could also throw and exception or do some other stuff here
MsgBox(String.Format("Array only has {0} items", part.Length))
Exit Sub
End If
'updates new episode numbers on buttons
Button20.Text = part(0)
Button30.Text = part(1)
Button40.Text = part(2)
...
Edit for the updated question
If you do have a problem like this, just approach it systematically and get as much information as you can. First you have to check if you really get the data you want from the remote source. To do that, add some logging (e.g. a MsgBox(newestversion) or a real log file). Check if the data you get is what you expect. If not, there's already a problem with your request/response code, which is a completely different problem than what I provided a solution for. If newestversion is OK, check if the splitting works by printing out the part() array. Maybe the server uses a different operating system or just uses vbCr as newline and not vbCrlf. If the splitting also works, you are done.
I have a text file with the format:
(title,price,id#)
CD1,11.00,111111
CD2,12.00,222222
CD3,13.00,333333
CD4,14.00,444444
CD5,15.00,555555
CD6,16.00,666666
What is the best way to go change the price of the appropriate CD if I'm given the id# and new price?
I'm sure it has something do to with getting the line and splitting it, but I'm not sure how I edit just one line and not mess up the whole file.
You can't rewrite a line without rewriting the entire file (unless the lines happen to be the same length). For such a small file it's probably the easiest to change the line in memory and then rewrite all to the file:
Dim idToFind = "444444"
Dim newPrice = "100"
Dim lines = IO.File.ReadAllLines(path)
For i = 0 To lines.Length - 1
Dim line = lines(i)
Dim fields = line.Split(","c)
If fields.Length > 2 Then
Dim id = fields(2)
If id = idToFind Then
Dim title = fields(0)
lines(i) = String.Format("{0},{1},{2}", title, newPrice, id)
Exit For
End If
End If
Next
IO.File.WriteAllLInes(path, lines)
Okay, now we know it's a short file, life becomes much easier:
Load the file into an array of lines using File.ReadAllLines
Find the right line using string.Split to split each line into the constituent parts, and check the ID.
When you've found the right line, replace it with the complete new line
Write the file back with File.WriteAllLines
That should be enough to get you going.
If its just a file with like 25 lines, you could do a simple input-transform-output routine and update the price per line.
Something like this (Using Streamreader / writer ).
Sub UpdatePrice(ByVal pricesToUpdate As Dictionary(Of Integer, String), ByVal inputPath As String)
If Not IO.File.Exists(inputPath) Then Return
Try
Using inputStream = New IO.StreamReader(inputPath, System.Text.Encoding.UTF8, True)
Using outputStream = New IO.StreamWriter(inputPath + ".tmp", False, System.Text.Encoding.UTF8)
While Not inputStream.EndOfStream
Dim inputLine = inputStream.ReadLine
Dim content = inputLine.Split(","c)
If Not content.Length >= 3 Then
outputStream.WriteLine(inputLine)
Continue While
End If
Dim id As Integer
If Not Integer.TryParse(content(2), id) Then
outputStream.WriteLine(inputLine)
Continue While
End If
If Not pricesToUpdate.ContainsKey(id) Then
outputStream.WriteLine(inputLine)
Continue While
End If
content(1) = pricesToUpdate(id)
outputStream.WriteLine(String.Join(",", {content(0), content(1), content(2)}))
End While
End Using
End Using
If IO.File.Exists(inputPath + ".tmp") Then
IO.File.Delete(inputPath)
IO.File.Move(inputPath + ".tmp", inputPath)
End If
Catch ex As IO.IOException
If IO.File.Exists(inputPath + ".tmp") Then IO.File.Delete(inputPath + ".tmp")
End Try
End Sub
I have some large csv files (1.5gb each) where I need to replace specific values. The method I'm currently using is terribly slow and I'm fairly certain that there should be a way to speed this up but I'm just not experienced enough to know what I should be doing. This is my first post and I tried searching through to find something relevant but didn't come across anything. Any help would be appreciated.
My other thought would be to break the file into chunks so that I can read the entire thing into memory, do all of the replacements there and then output to a consolidated file. I tried this but the way I did it actually ended up seeming slower than my current method.
Thanks!
Sub Main()
Dim fName As String = "2009.csv"
Dim wrtFile As String = "2009.1.csv"
Dim lRead
Dim lwrite As String
Dim strRead As New System.IO.StreamReader(fName)
Dim strWrite As New System.IO.StreamWriter(wrtFile)
Dim bulkWrite As String
bulkWrite = ""
Do While strRead.Peek <> -1
lRead = Split(strRead.ReadLine(), ",")
If lRead(9) = "5MM+" Then lRead(9) = "5000000"
If lRead(9) = "1MM+" Then lRead(9) = "1000000"
lwrite = ""
For i = LBound(lRead) To UBound(lRead)
lwrite = lwrite & lRead(i) & ","
Next
strWrite.WriteLine(lwrite)
Loop
strRead.Close()
strWrite.Close()
End Sub
You are splitting and the combining, which can take some time.
Why not just read the line of text. Then replace any occurance of "5MM+" and "1MM+" with the approiate value and then write the line.
Do While ...
s = strRead.ReadLine();
s = s.Replace("5MM+", "5000000")
s = s.Replace("1MM+", "1000000")
strWrite(s);
Loop