I was kindly helped before with this code by a guy name Steven, however I have hit yet another stumbling block, I keep messing my loops up.
I have some code that cycles through over 100 ish k of Find and Replaces and i have added into it the ability to cycle through a number of
files to Find and Replace items within said files, i have used ReadLine and WriteLine otherwise I have memory issues and it bombs out.
With the code below,i can get it to either cycle through and not find and replace or find and replace one of the files and not cycle
through the rest of the files. Where am i going wrong with the loops, im going insane. Many thanks, VBvirg
'The files to cycle through
For Each row2 As DataGridViewRow In DataGridView2.Rows
If Not row2.IsNewRow Then
Dim DateFile As String = row2.Cells(1).Value.ToString
Dim DateFileConv As String = row2.Cells(2).Value.ToString
Dim fName As String = DateFile
Dim wrtFile As String = DateFileConv
Dim strRead As New System.IO.StreamReader(fName)
Dim strWrite As New System.IO.StreamWriter(wrtFile)
While True
'Thesre are the find and replaces
Dim line As String = strRead.ReadLine()
If line IsNot Nothing Then
For Each row As DataGridViewRow In DataGridView1.Rows
If Not row.IsNewRow Then
Dim Find1 As String = row.Cells(0).Value.ToString
Dim Replace1 As String = row.Cells(1).Value.ToString
line = line.Replace(Find1, Replace1)
End If
Next
strWrite.WriteLine(line)
End If
End While
End If
Next
Cursor.Current = Cursors.Default
MessageBox.Show("Finished Replacing")
Related
in my File Text I have the following things:
I have to make it start from somewhere and stop at a certain point.
but he only starts from that point, but he does not know how to stop at one point.
[Letters]
A
B
C
D
E
[Loop]
[Words]
Fish
Facebook
Google
Youtube
I should display Expected Output:
A
B
C
D
E
Then I should make it display
Fish
Facebook
Google
Youtube
but it shows me:
[Letters]
A
B
C
D
E
[Loop]
[Words]
Fish
Facebook
Google
Youtube
Code
Dim line As String
Using reader As StreamReader = New StreamReader(My.Application.Info.DirectoryPath & "\TestReader.txt")
line = reader.ReadLine
Dim sb As New StringBuilder
Do
Do
If reader.Peek < 0 Then 'Check that you haven't reached the end
Exit Do
End If
line = reader.ReadLine
If line.StartsWith("[Letters]") AndAlso line.EndsWith("[Loop]") Then 'Check if we have reached another check box.
Exit Do
End If
sb.AppendLine(line)
Loop
TextBox1.Text = sb.ToString
sb.Clear()
Loop Until reader.Peek < 0
End Using
This assumes that startPrefix and endPrefix will always be present in the file:
Dim startPrefix As String 'Set as required
Dim endPrefix As String 'Set as required
Dim lines As New List(Of String)
Using reader As New StreamReader("file path here")
Dim line As String
'Skip lines up to the first starting with the specified prefix.
Do
line = reader.ReadLine()
Loop Until line.StartsWith(startPrefix)
line = reader.ReadLine()
Do Until line.StartsWith(endPrefix)
lines.Add(line)
line = reader.ReadLine()
Loop
End Using
'Use lines here.
Are you really sure that you want to look for lines that start with those markers though? Wouldn't you really prefer to look for lines that are equal to those markers?
EDIT:
You could - and probably should - encapsulate that functionality in a method:
Private Function GetLinesBetween(filePath As String, startPrefix As String, endPrefix As String) As String()
Dim lines As New List(Of String)
Using reader As New StreamReader(filePath)
Dim line As String
'Skip lines up to the first starting with the specified prefix.
Do
line = reader.ReadLine()
Loop Until line.StartsWith(startPrefix)
line = reader.ReadLine()
'Take lines up to the first starting with the specified prefix.
Do Until line.StartsWith(endPrefix)
lines.Add(line)
line = reader.ReadLine()
Loop
End Using
Return lines.ToArray()
End Function
In my program, I collect bits of information on a massive scale, hundreds of thousands to millions of lines each. I am trying to limit each file I create to a certain size in order to be able to quickly open it and read the data. I am using a HashSet to collect all the data without duplicates.
Here's my code so far:
Dim Founds As HashSet(Of String)
Dim filename As String = (Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\Sorted_byKING\sorted" + Label4.Text + ".txt")
Using writer As New System.IO.StreamWriter(filename)
For Each line As String In Founds
writer.WriteLine(line)
Next
Label4.Text = Label4.Text + 1 'Increments sorted1.txt, sorted2.txt etc
End Using
So, my question is:
How do I go about saving, let's say 250,000 lines in a text file before moving to another one and adding the next 250,000?
First of all, do not use Labels to simply store values. You should use variables instead, that's what variables are for.
Another advice, always use Path.Combine to concatenate paths, that way you don't have to worry about if each part of the path ends with a separator character or not.
Now, to answer your question:
If you'd like to insert the text line by line, you can use something like:
Sub SplitAndWriteLineByLine()
Dim Founds As HashSet(Of String) 'Don't forget to initialize and fill your HashSet
Dim maxLinesPerFile As Integer = 250000
Dim fileNum As Integer = 0
Dim counter As Integer = 0
Dim filename As String = String.Empty
Dim writer As IO.StreamWriter = Nothing
For Each line As String In Founds
If counter Mod maxLinesPerFile = 0 Then
fileNum += 1
filename = IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop),
$"Sorted_byKING\sorted{fileNum.ToString}.txt")
If writer IsNot Nothing Then writer.Close()
writer = New IO.StreamWriter(filename)
End If
writer.WriteLine(line)
counter += 1
Next
writer.Dispose()
End Sub
However, if you will be inserting the text from the HashSet as is, you probably don't need to write line by line, instead you can write each "bunch" of lines at once. You could use something like the following:
Sub SplitAndWriteAll()
Dim Founds As HashSet(Of String) 'Don't forget to initialize and fill your HashSet
Dim maxLinesPerFile As Integer = 250000
Dim fileNum As Integer = 0
Dim filename As String = String.Empty
For i = 0 To Founds.Count - 1 Step maxLinesPerFile
fileNum += 1
filename = IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop),
$"Sorted_byKING\sorted{fileNum.ToString}.txt")
IO.File.WriteAllLines(filename, Founds.Skip(i).Take(maxLinesPerFile))
Next
End Sub
i'm trying to importe a csv file after creating on the same application, the only probleme is that even if a string matchs a line from the file, comparing them on vb.net dosn't give a true boolean i know i didn't make any mistakes because of the line with the commentary 'THIS LINE , i use a pretty small list to do my test and in that loop, there is always one element that matches exactly the string, but comparing them on vb.net dosn't return a true. the result of this is that just after saving the file to my computer while still having it on my listview1 on the application, i load it to the application again and it duplicates everything
Dim open As New OpenFileDialog
open.Filter = "CSV Files (*.csv*)|*.csv"
If open.ShowDialog = Windows.Forms.DialogResult.OK Then
Dim File As String = My.Computer.FileSystem.ReadAllText(open.FileName)
Dim lines() As String = File.Split(Environment.NewLine)
For i = 1 To (lines.Count - 1)
Dim line As String = lines(i)
Dim Columns() As String = line.Split(";")
Dim addLin As New ListViewItem(Columns)
Dim Alr As Boolean = False
Dim st as string=listView1.Items.Item(k).SubItems.Item(0).Text
For k = 0 To (ListView1.Items.Count - 1)
Dim st as string=listView1.Items.Item(k).SubItems.Item(0).Text
MsgBox(Columns(0)& Environment.NewLine & st) 'THIS LINE
If ListView1.Items.Item(k).SubItems.Item(0).Text = Columns(0) Then
Alr = True
MsgBox("true") 'never showsup even when the previous one show the match
End If
next
If Alr = False Then
MsgBox("false") 'the msgbox is only to check
ListView1.Items.Add(addLin)
End If
next
end if
I'm currently using the following to read the contents of all text files in a directory into an array
Dim allLines() As String = File.ReadAllLines(txtfi.FullName)
Within the text files are only 6 lines that all follow the same format and will read something like
forecolour=black
I'm trying to then search for the word "forecolour" and retrieve the information after the "=" sign (black) so i can then populate the below code
AllDetail(numfiles).uPath = ' this needs to be the above result
I've only posted parts of the code but if it helps i can post the rest. I just need a little guidance if possible
Thanks
This is the full code
Dim numfiles As Integer
ReDim AllDetail(0 To 0)
numfiles = 0
lb1.Items.Clear()
Dim lynxin As New IO.DirectoryInfo(zMailbox)
lb1.Items.Clear()
For Each txtfi In lynxin.GetFiles("*.txt")
Dim allLines() As String = File.ReadAllLines(txtfi.FullName)
ReDim Preserve AllDetail(0 To numfiles)
AllDetail(numfiles).uPath = 'Needs to be populated
AllDetail(numfiles).uName = 'Needs to be populated
AllDetail(numfiles).uCode = 'Needs to be populated
AllDetail(numfiles).uOps = 'Needs to be populated
lb1.Items.Add(IO.Path.GetFileNameWithoutExtension(txtfi.Name))
numfiles = numfiles + 1
Next
End Sub
AllDetail(numfiles).uPath = Would be the actual file path
AllDetail(numfiles).uName = Would be the detail after “unitname=”
AllDetail(numfiles).uCode = Would be the detail after “unitcode=”
AllDetail(numfiles).uOps = Would be the detail after “operation=”
Within the text files that are being read there will be the following lines
Unitname=
Unitcode=
Operation=
Requirements=
Dateplanned=
For the purpose of this array I just need the unitname, unitcode & operation. Going forward I will need the dateplanned as when this is working I want to try and work out how to only display the information if the dateplanned matches the date from a datepicker. Hope that helps and any guidance or tips are gratefully received
If your file is not very big you could simply
Dim allLines() As String = File.ReadAllLines(txtfi.FullName)
For each line in allLines
Dim parts = line.Split("="c)
if parts.Length = 2 andalso parts(0) = "unitname" Then
AllDetails(numFiles).uName = parts(1)
Exit For
End If
Next
If you are absolutely sure of the format of your input file, you could also use Linq to remove the explict for each
Dim line = allLines.Where(Function(x) (x.StartsWith("unitname"))).SingleOrDefault()
if line IsNot Nothing then
AllDetails(numFiles).uName = line.Split("="c)(1)
End If
EDIT
Looking at the last details added to your question I think you could rewrite your code in this way, but still a critical piece of info is missing.
What kind of object is supposed to be stored in the array AllDetails?
I suppose you have a class named FileDetail as this
Public class FileDetail
Public Dim uName As String
Public Dim uCode As String
Public Dim uCode As String
End Class
....
numfiles = 0
lb1.Items.Clear()
Dim lynxin As New IO.DirectoryInfo(zMailbox)
' Get the FileInfo array here and dimension the array for the size required
Dim allfiles = lynxin.GetFiles("*.txt")
' The array should contains elements of a class that have the appropriate properties
Dim AllDetails(allfiles.Count) as FileDetail
lb1.Items.Clear()
For Each txtfi In allfiles)
Dim allLines() As String = File.ReadAllLines(txtfi.FullName)
AllDetails(numFiles) = new FileDetail()
AllDetails(numFiles).uPath = txtfi.FullName
Dim line = allLines.Where(Function(x) (x.StartsWith("unitname="))).SingleOrDefault()
if line IsNot Nothing then
AllDetails(numFiles).uName = line.Split("="c)(1)
End If
line = allLines.Where(Function(x) (x.StartsWith("unitcode="))).SingleOrDefault()
if line IsNot Nothing then
AllDetails(numFiles).uName = line.Split("="c)(1)
End If
line = allLines.Where(Function(x) (x.StartsWith("operation="))).SingleOrDefault()
if line IsNot Nothing then
AllDetails(numFiles).uOps = line.Split("="c)(1)
End If
lb1.Items.Add(IO.Path.GetFileNameWithoutExtension(txtfi.Name))
numfiles = numfiles + 1
Next
Keep in mind that this code could be really simplified if you start using a List(Of FileDetails)
I'm building a program that gets the publisher of the book by scanning its title page and using OCR … since publishers are always at the bottom of the title page I'm thinking that a detecting lines that are separated by space is a solution but I don't know how to test for that. Here is my code:
Dim builder As New StringBuilder()
Dim reader As New StringReader(txtOCR.Text)
Dim iCounter As Integer = 0
While True
Dim line As String = reader.ReadLine()
If line Is Nothing Then Exit While
'i want to put the condition here
End While
txtPublisher.Text = builder.ToString()
Do you mean empty lines? Then you can do this:
Dim bEmpty As Boolean
And then inside the loop:
If line.Trim().Length = 0 Then
bEmpty = True
Else
If bEmpty Then
'...
End If
bEmpty = False
End If
Why not do the following: from the bottom, go up until you find the first non-empty line (no idea how the OCR works … maybe the bottom-most line is always non-empty, in which case this is redundant). In the next step, go up until the first empty line. The text in the middle is the publisher.
You don’t need the StringReader for that:
Dim lines As String() = txtOCR.Text.Split(Environment.NewLine)
Dim bottom As Integer = lines.Length - 1
' Find bottom-most non-empty line.
Do While String.IsNullOrWhitespace(lines(bottom))
bottom -= 1
Loop
' Find empty line above that
Dim top As Integer = bottom - 1
Do Until String.IsNullOrWhitespace(lines(top))
top -= 1
Loop
Dim publisherSubset As New String(bottom - top)()
Array.Copy(lines, top + 1, publisherSubset, 0, bottom - top)
Dim publisher As String = String.Join(Environment.NewLine, publisherSubset)
But to be honest I don’t think this is a particularly good approach. It’s inflexible and doesn’t cope well with unexpected formatting. I’d instead use a regular expression to describe what the publisher string (and its context) looks like. And maybe even that isn’t enough and you have to put some thought into describing the whole page to extrapolate which of the bits is the publisher.
Assuming the publisher is always on the last line and always comes after an empty line. Then perhaps the following?
Dim Lines as New List(Of String)
Dim currentLine as String = ""
Dim previousLine as String = ""
Using reader As StreamReader = New StreamReader(txtOCR.Txt)
currentLine = reader.ReadLine
If String.IsNullOrWhiteSpace(previousLine) then lines.Add(currentLine)
previousLine = currentLine
End Using
txtPublisher.Text = lines.LastOrDefault()
To ignore if the previous line is blank/empty:
Dim Lines as New List(Of String)
Using reader As StreamReader = New StreamReader(txtOCR.Txt)
lines.Add(reader.ReadLine)
End Using
txtPublisher.Text = lines.LastOrDefault()