Following this, I use a TextFieldParser to read a csv File:
Sub imp1(path As String)
With New TextFieldParser("C:\matrix1.csv")
.TextFieldType = FileIO.FieldType.Delimited
.Delimiters = New String() {";"}
.CommentTokens = New String() {"'"}
Debug.Print(.ReadToEnd)
' some more code to read the contents into a 2d-array
End with
End Sub
After setting .CommentTokens = New String() {"'"} I expected lines with leading single quotes being skipped.
However, from what I gather there is no difference at all when reading a csv like the following:
'comment1
1;0.5;0.9;0.3
0.5;1;0.6;0.2
0.9;0.6;1;0.1
0.3;0.2;0.1;1
I tried replacing the single quote ' with several common comment-characters (#, \, \*), both with and without a following blanks - still not getting the desired results.
In your code you are using TextFieldParser.ReadToEnd which simply returns the complete remaining text and does not ignore comments. This is documented:
The ReadToEnd method does not ignore blank lines and comments.
If you would use ReadFields the comments would be ignored (MS example):
While Not MyReader.EndOfData
Try
currentRow = MyReader.ReadFields()
' Include code here to handle the row.
Catch ex As Microsoft.VisualBasic.FileIO.MalformedLineException
MsgBox("Line " & ex.Message &
" is invalid. Skipping")
End Try
End While
Related
I'm not sure what is wrong with my code. It reads the PDF file, and grabs all the text, but every item is combined together into one string with no separator of any kind.
Sample:
"Houses: 2
Bedrooms: 3
Bathsroom 4"
will get read as "Houses: 2Bedrooms: 3Bathsroom 4"
I've searched through all of the examples to no avail. I've also tried LocationTextExtractionStrategy to no avail. I've tried using the .split method and no help.
Public Shared Function ParseAllPdfText(ByVal filepath As String)
Dim sbtxt, currenttext As String
sbtxt = ""
Try
Using reader As New PdfReader(filepath)
For intPages As Integer = 1 To reader.NumberOfPages
currenttext = PdfTextExtractor.GetTextFromPage(reader, intPages, New LocationTextExtractionStrategy())
currenttext = Encoding.UTF8.GetString(ASCIIEncoding.Convert(Encoding.[Default], Encoding.UTF8, Encoding.[Default].GetBytes(currenttext)))
sbtxt = sbtxt & currenttext & vbcrlf
Next
End Using
Catch ex As Exception
MsgBox(" There was an error extracting text from the file: " & ex.Message, vbInformation, "Error Extracting Text")
End Try
Return sbtxt
Nevermind, this was an oversight on my part. I realized the lines are separated by Chr(10). Chr(10) does not create a new line in textboxes, which is where I was outputting my string. It DOES however create a new line in MsgBox. So if anyone else runs into this problem, chr(10) is the separator. :-)
I am trying to read specific lines from a text file in an array (e.g. line 16,25,34, and so on). Could you please let me know if it is possible and how that could be done?
Thanks in advance,
Pouya
Yes it is possible. Since this is not a code based will elaborate how to achieve that. This will depends on the size of your target file. If the size in not to large for your PC's memory then you can read the whole textfile while reading keep the count.
Then start when the file has been read to end to go through your lines using regex.
Check:
VB.NET Read Certain text in a text file
your solution is here:
http://www.dreamincode.net/forums/topic/56497-go-to-a-particular-line-in-a-text-file-using-vbnet/
How to read a specific line from a text file in VB
Ok, here's I've also quoted the code to help you from the second last like I provided above. I'm sure you know how to get data from an Array so instead of line you will add your array.
Public Function
ReadSpecifiedLine(ByVal line As
Integer) As String
'create a variable to
hold the contents of the file
Dim contents As String = String.Empty
'create a variable to
hold our line contents
Dim lineText As String =
String.Empty
' always use a
try...catch to deal
' with any exceptions
that may occur
Try
'Using lineByLine As New IO.StreamReader(_fileName)
Dim lineCount As Integer = 0
While Not lineByLine.EndOfStream
lineByLine.ReadLine ()
If lineCount = line Then
' you can replace the line variable above or use the And Or to match the lines from your array.
lineText = lineByLine.ReadLine()
End If
lineCount += 1
End While
End Using
Catch ex As FileNotFoundException
lineText = String.Empty
_returnMessage = ex.Message
Catch ex As Exception
' deal with any errors
_returnMessage = ex.Message
End Try
Return lineText
End Function
Hope this helps you.(Sorry having some problems in code formatting it some part maybe not formeted, or visible. If End Function is not visible please refer to the link. I've tried so many times to formet this but it not properly formeted, I'm using a Mobile phone.)
I have a program that needs to look through a text file line by line, the lines look like this:
10-19-2015 Brett Reinhard All Bike Yoga Run the Studio Design Your Own Strength
These are separated by tabs in the text file.
What I want to do is look at the second value, in this case "Brett Reinhard" and move the full line to another textfile called "Brett Reinhard"
I was thinking of using an array to check to see if the second 'column' in the line matched any value within a given array, if it does I want to perform a specific action.
The way I am thinking of doing this is with a For/next statement, now while it will work it will be a laborious process for the computer that I will be using it on.
The code I am thinking of using looks like this:
For intCounter=0 to Whatever Number is the last number of the array
If currentfield.contains(array(intCounter)) Then
Open StreamWriter(File directory & array(intcounter) & ".txt")
Streamwriter.Writeline(currentfield)
End IF
Is there a better way of doing this, such as referencing the second 'column' in the line, similar to the syntax used in VBA for excel.
Name=Cells(1,2).Value
If you can guarantee that a line will only use the tab characters as field separators, you can do something along this:
Open the stream for reading text
Open a stream for writing text
Read a line of text
Use the Split method to break the incoming line into an array of fields
If the second element in the array is your sentinel value, write the original line to the writer
Repeat yourself until you have reached the end of file (ReadLine will return Nothing, or null for those c# folk).
Close and dispose of your stream objects.
If you aren't sure of the format, you will want to take the hit and use the TextFieldParser as mentioned in an earlier comment.
So while its not using an array to search a file, what I ended up doing works just as well. I ended up using the split method thanks to #Martin Soles.
Here is what I came up with:
Sub Main()
Dim intCount As Integer = 1
Dim words As String
Dim split As String()
Using MyReader As New Microsoft.VisualBasic.
FileIO.TextFieldParser(
"I:\Games, Events, & Promotions\FRP\Back End\Approved.txt")
MyReader.TextFieldType = FileIO.FieldType.Delimited
MyReader.SetDelimiters(",")
Dim currentRow As String()
While Not MyReader.EndOfData
Try
currentRow = MyReader.ReadFields()
Dim currentField As String
For Each currentField In currentRow
words = currentField
split = words.Split(New [Char]() {CChar(vbTab)})
For Each s As String In split
If intCount = 2 Then
Dim file As System.IO.StreamWriter
file = My.Computer.FileSystem.OpenTextFileWriter("I:\Games, Events, & Promotions\FRP\Back End\" & s & ".txt", True)
file.WriteLine(currentField)
file.Close()
End If
intCount = intCount + 1
Next s
intCount = 1
Next
Catch ex As Microsoft.VisualBasic.
FileIO.MalformedLineException
MsgBox("Line " & ex.Message &
"is not valid and will be skipped.")
End Try
End While
End Using
End Sub 'Main
Thank you guys for the suggestions.
For right now the split method will work for what is needed.
I have the following code that I am using to parse out a test file. I am getting variable conversion error in Sub Main() when I assign file = Read(). The return value of Read() is a TextFieldParser type. How do I assign the proper variable type to "file" so I can write the output to a text file?
Thanks!
Module Module1
Function Read()
Using MyReader As New FileIO.TextFieldParser("C:\Users\Colin\Desktop\Parse_Me.txt")
Dim currentRow As String
While Not MyReader.EndOfData
Try
currentRow = MyReader.ReadLine()
Console.WriteLine(Parse_me(currentRow))
Catch ex As FileIO.MalformedLineException
MsgBox("Line " & ex.Message &
" is invalid. Skipping")
End Try
End While
Return MyReader
MyReader.Close()
End Using
End Function
Function Parse_me(ByVal test As String)
Dim Set_1, Set_2, Set_3, Set_4, Set_5 As String
Dim new_string As String
Set_1 = test.Substring(0, 4)
Set_2 = test.Substring(7, 2)
Set_3 = test.Substring(11, 1)
Set_4 = test.Substring(14, 4)
Set_5 = test.Substring(20, 4)
new_string = Set_1 & " " & Set_2 & " " & Set_3 & " " & Set_4 & " " & Set_5
Return new_string
End Function
Sub Main()
Dim file As Object
file = Read()
FilePutObject("C:\Users\Colin\Desktop\Parse_Meoutput.txt", file)
End Sub
End Module
Here's how FilePutObject is supposed to work (example taken from MSDN documentation for FilePutObject):
Sub WriteData()
Dim text As String = "test"
FileOpen(1, "test.bin", OpenMode.Binary)
FilePutObject(1, text)
FileClose(1)
End Sub
The 1 act as an identifier for the file. Note also that the file name is passed to FileOpen before calling FilePutObject, and that FileClose is called afterwards. Also note that a string is being written to the file. I don't know which types of data are valid for being passed to FilePutObject, but FileIO.TextFieldParser is definitely not one of them (I just tried it).
Correct me if I'm wrong, but I'm pretty sure that FilePutObject is one of those carry-overs from VB6. If you're writing new code, I would rather use a Stream object for my I/O. For one, it's a lot more .Net-ish (i.e., type-safe, object-oriented, etc). And as far as usability goes, it's a lot clearer how a Stream works, not to mention it doesn't involve passing arbitrary integers as handles to functions in order to identify which file you'd like to work with. And to top it all off, a Stream works whether you want to write to a file, to the console, or send the data to another machine. To sum up, I would definitely look up the Stream class, some of its child classes (like FileStream, and whatever else appeals to you), and some associated types (such as the TextWriter class for conveniently writing text).
Change the definition of the function "read" to:
Function Read() as FileIO.TextFieldParser
and change the declaration of "file" in sub main to:
Dim file as FileIO.TextFieldParser
That way the data type of the function and assignment match.
Hey guys, just another little problem here! Trying to write a quiz for a college portfolio and having trouble with writing to a .txt textfile. On one form(form4.vb), I have a listbox that picks up the information held within a notepad textfile called "usernames" which contains names of quiz users. When written in manually to this textfile, my listbox picks it up fine, however, on a different form(form3.vb), I have a textbox where a user inputs their name, this is supposed to go to the "usernames.txt" textfile to be picked up by the listbox on the other form but instead, it does not write anything at all and if there is already text on this textfile, it wipes it all out.
I also have to use the application.startup path instead of the usual C:\my documentents\ etc so i would have to begin with something like this: (Note: code is a little mixed up due to messing around with different variations but this is just a example)
'Try
' Dim appPath As String
' Dim fileName As String
' appPath = Application.StartupPath
' fileName = appPath & "\usernames.txt"
' sWriter = New System.IO.StreamWriter(fileName)
' sWriter.Close()
' MessageBox.Show("Writing file to disk")
'Catch ex As Exception
' MessageBox.Show("File Access Error", "Error")
'End Try
'MessageBox.Show("Program terminating")
'Application.Exit()
Hope someone can help! =)
You want something more like this:
Dim appPath As String = Application.StartupPath
Dim fileName As String = IO.Path.Combine(appPath, "usernames.txt")
Try
IO.File.AppendAllText(fileName, TextBox1.Text & Environment.NewLine)
Catch ex As Exception
MessageBox.Show("File Access Error", "Error")
End Try
MessageBox.Show("Program terminating")
Environment.Exit()
Some things worth noting in this code:
Path.Combine() as the correct way to add the separator character
File.AppendAllText() is much easier for simple things than messing with streamreader/writer. Pair it with File.ReadAllText() or File.ReadAllLines() in the other direction.
Environment.Exit() vs Application.Exit()
Where is your dim statement for sWriter (streamWriter)?