I'm trying like crazy to figure out how to do this. I need to look at a textfile that I've designed (for a quiz program)- line by line (the line having two parts separated by a comma) for the question (First part) and the boolean answer (second part). Ie. A line from the text file will look like:
You have 10 fingers,true
you have 10 toes,true
you have 2 thumbs,true
I just need to be able to convert this to an array whereby I can access the elements on command, so for instance (0,0) would display the first question in a textbox, and I would reference the users answer (in the form of true or false) against (0,1) where I would use a counter to count the number of correct answers. After the user answers the first question I could loop to the second question to be displayed in the array and so forth. Although there may be more advanced ways of doing this I will need to use a stream reader in this context.
I see I can read ONE line into an array with :
dim line() as string = io.file.readalllines("C:\data.txt")
dim value(2) as integer
value = line.split(","c)
but I need to access each line, with their answers, one at a time. If I could get the textfile into an two dimensional array I could simply access each element on command. Help :)
Any help would be GREATLY appreciated!
I suggest to use a proper class to handle your data. For example you could write a class named QA that stores the Question text and the boolean value of the answer
Public Class QA
Public Question as String
Public Answer as Boolean
End Class
You could read your file with File.ReadLines or use the StreamReader class.
Sub Main
' A list of QA objects loaded from file
Dim qaList as New List(Of QA)()
Using sw = new StreamReader("C:\data.txt")
Dim line as String
Do
line = sw.ReadLine()
If line Is Nothing Then Exit Do
Dim parts() = line.Split(","c)
' Initialize a new QA object and add it to the list
qaList.Add(new QA() _
With
{
.Question = parts(0),
.Answer = Convert.ToBoolean(parts(1))
})
Loop
End Using
Now you could use the List(Of QA) as an array referencing the elements using an indexer
Console.WriteLine(qaList(0).Question)
Console.WriteLine(qaList(0).Answer)
End Sub
Related
I'm trying to make a small VB program to remove duplicate lines and empty lines from plain text.
I have the RichTextBox input but eventually I do not know what the type of the returned object is, is it an array or a list maybe ?
Also I'm trying to find the most efficient way to remove duplicate lines from big plain text(s), in Python I do it this way :
lines_nodupes = {}
for elt in lines :
lines_nodupes[elt] = ""
Since you can not have twice the same key, no duplicates are kept in the lines_nodupes dictionnary and I can enumerate it to access the lines.
There are two properties you can use :
Lines will return an array of Strings
Text will return the entire text as a string
See RichTextBox from MSDN
If you want to do as in Python :
Dim noDup as new Dictionary(Of String, String)
For Each line in MyRichTextBox.Lines
if not noDup.ContainsKey(line) then
noDUp.add(line, "")
End if
Next
You can also do (as suggested by VisualVincent in the coments) :
Dim noDup as new List(Of String)
For Each line in MyRichTextBox.Lines
if not noDup.Contains(line) then
noDUp.add(line)
End if
Next
which is a bit slower but difference won't be seen unless you have a very long list of items.
First, I am not a programmer, I mainly just do simple scripts however there are somethings that are just easier to do in VB, I am pretty much self taught so forgive me if this sounds basic or if I can't explain it to well.
I have run into an issue trying to load a multi-column text file into a list box. There are two separate issues.
First issue is to read the text file and only grab the first column to use in the listbox, I am currently using ReadAllLines to copy the text file to a string first.
Dim RDPItems() As String = IO.File.ReadAllLines(MyDocsDir & "\RDPservers.txt")
However I am having a difficult time finding the correct code to only grab the first Column of this string to put in the listbox, if I use the split option I get an error that "Value of type '1-dimensional array of String' cannot be converted to 'String'"
The code looked like
frmRDP.lstRDP.Items.Add() = Split(RDPItems, ";", CompareMethod.Text)
This is the first hurdle, the second issue is what I want to do is if an item is selected from the List box, the value of the second column gets pulled into a variable to use.
This part I'm not even sure where to begin.
Example data of the text file
Server1 ; 10.1.1.1:3389
Server2 ; 192.168.1.1:8080
Server3 ; 172.16.0.1:9833
.....
When it's working the application will read a text file with a list of servers and their IPs and put the servers in a listbox, when you select the server from the listbox it and click a connect button it will then launch
c:\windows\system32\mstsc.exe /v:serverip
Any help would be appreciated, as I can hard code a large list of this into the VB application it would be easier to just have a text file with a list of servers and IPs to load instead.
The best practise for this would probably be to store your "columns" in a Dictionary. Declare this at class level (that is, outside any Sub or Function):
Dim Servers As New Dictionary(Of String, String)
When you load your items you read the file line-by-line, adding the items to the Dictionary and the ListBox at the same time:
Using Reader As New IO.StreamReader(IO.Path.Combine(MyDocsDir, "RDPservers.txt")) 'Open the file.
While Reader.EndOfStream = False 'Loop until the StreamReader has read the whole file.
Dim Line As String = Reader.ReadLine() 'Read a line.
Dim LineParts() As String = Line.Split(New String() {" ; "}, StringSplitOptions.None) 'Split the line into two parts.
Servers.Add(LineParts(0), LineParts(1)) 'Add them to the Dictionary. LineParts(0) is the name, LineParts(1) is the IP-address.
lstRDP.Items.Add(LineParts(0)) 'Add the name to the ListBox.
End While
End Using 'Dispose the StreamReader.
(Note that I used IO.Path.Combine() instead of simply concatenating the strings. I recommend using that instead for joining paths together)
Now, whenever you want to get the IP-address from the selected item you can just do for example:
Dim IP As String = Servers(lstRDP.SelectedItem.ToString())
Hope this helps!
EDIT:
Missed that you wanted to start a process with it... But it's like charliefox2 wrote:
Process.Start("c:\windows\system32\mstsc.exe", "/v:" & Servers(lstRDP.SelectedItem.ToString()))
Edit: #Visual Vincent's answer is way cleaner. I'll leave mine, but I recommend using his solution instead. That said, scroll down a little for how to open the server. He's got that too! Upvote his answer, and mark it as correct!
It looks like you're trying to split an array. Also, ListBox.Items.Add() works a bit differently than the way you've written your code. Let's take a look.
ListBox.Items.Add() requires that you provide it with a string inside the parameters. So you would do it like this:
frmRDP.lstRDP.Items.Add(Split(RDPItems, ";", CompareMethod.Text))
But don't do that!
When you call Split(), you must supply it with a string, not an array. In this case, RDPItems is an array, so we can't split the entire thing at once. This is the source of the error you were getting. Instead, we'll have to do it one item at a time. For this, we can use a For Each loop. See here for more info if you're not familiar with the concept.
A For Each loop will execute a block of code for each item in a collection. Using this, we get:
For Each item In RDPItems
Dim splitline() As String = Split(item, ";") 'splits the item by semicolon, and puts each portion into the array
frmRDP.lstRDP.Items.Add(splitline(0)) 'adds the first item in the array
Next
OK, so that gets us our server list put in our ListBox. But now, we want to open the server that our user has selected. To do that, we'll need an event handler (to know when the user has double clicked something), we'll have to find out which server they selected, and then we'll have to open that server.
We'll start by handling the double click by creating a sub to deal with it:
Private Sub lstRDP_MouseDoubleClick(sender As Object, e As MouseEventArgs) Handles lstRDP.MouseDoubleClick
Next, we'll get what the user has selected. Here, we're setting selection equal to the index that the user has selected (in this case, the first item is 0, the second is 1, and so on).
Dim selection As Integer = lstRDP.SelectedIndex
Lastly, we need to open the server. I'm assuming you want to do that in windows explorer, but if I'm mistaken please let me know.
Dim splitline() As String = Split(RDPItems(selection), ";")
Dim location As String = Trim(splitline(1))
We'll need to split the string again, but you'll notice this time I'm choosing the item whose location in the array is the same as the index of the list box the user has selected. Since we added our items to our listbox in the order they were added to our array, the first item in our listbox will be the first in the array, and so on. The location of the server will be the second part of the split function, or splitline(1). I've also included the Trim() function, which will remove any leading or trailing spaces.
Finally, we need to connect to our server. We'll use Process.Start() to launch the process.
Process.Start("c:\windows\system32\mstsc.exe", "/v:" & location)
For future reference, to first argument for Process.Start() is the location of the process, and the second argument is any argument the process might take (in this case, what to connect to).
Our final double click event handler looks something like this:
Private Sub lstRDP_MouseDoubleClick(sender As Object, e As MouseEventArgs) Handles lstRDP.MouseDoubleClick
Dim selection As Integer = lstRDP.SelectedIndex
Dim splitline() As String = Split(RDPItems(selection), ";")
Dim location As String = Trim(splitline(1))
Process.Start("c:\windows\system32\mstsc.exe", "/v:" & location)
End Sub
A final note: You may need to put
Dim RDPItems() As String = IO.File.ReadAllLines(MyDocsDir & "\RDPservers.txt")
outside of a sub, and instead just inside your class. This will ensure that both the click handler and your other sub where you populate the list box can both read from it.
Using VB.NET (VS2013) I'd like to read a delimited file and remove a field if all records have the same blank field (could be multiple fields per record). The delimited file can have "x" number of columns and "y" number of rows and once the blank fields are removed, I need to write it back out as a new delimited file.
The input file will have a header that has to be maintained and the order of the records has to be maintained. I'm familiar with using TextParser to read the file and familiar with writing the file -- what I need help with is reading for a blank field and removing it if it exists across the entire file.
I was thinking I would have to use a datagrid but never used them so looking for some insight to point me in the direction.
Thanks!
I assume each line is delimited with a newline... open as a text file, read a line at a time and use the Split method to break up the line into an array of strings. The split method will take an argument that defines the delimiter you are using. Open the destination file and write the array of strings using a loop.
UPDATE
After thinking about it, you may have records that have a couple of blank columns and the rest have data. I'm not sure if you'd want to remove those columns, because you would lose the structure of the row if you did.
So instead of using StringSplitOptions.RemoveEmptyEntries, you can just do the Split() and then perform some Linq to find out if the Split() produced an array of empty strings.
Something like (with the same results)...
Imports System
Imports System.Linq
Public Module Module1
Public Sub Main()
Dim data As String = "|||||"
Dim pieces As String() = data.Split("|"c)
If pieces.Where(Function(p) String.IsNullOrEmpty(p) = False).Count = 0 Then
Console.WriteLine("All elements are empty")
Else
' Do something
End If
End Sub
End Module
Demo
OLD ANSWER
The String.Split() has an overload that excepts StringSplitOptions. Use StringSplitOptions.RemoveEmptyEntries with your String.Split() and if all records are blank then you'll end up with an array with a length of 0 that you can ignore.
Imports System
Public Module Module1
Public Sub Main()
Dim data As String = "|||||"
Dim pieces As String() = data.Split(new Char() {"|"}, StringSplitOptions.RemoveEmptyEntries)
If pieces.length = 0 Then
Console.WriteLine("All elements are empty")
Else
' Do something
End If
End Sub
End Module
Results:
All elements are empty
Demo
Im sure someone out there can help, im totally new to coding but getting into it and really enjoying. I know this is such a simple question out there for you folks but i have the following, I load a spread sheet of strings (2 columns) into a datagridview the reason i do this because there is over 100,000 find and replaces and these will generally sit within and existing string when searching, then from there i want to simply search a txt file and find and replace a number of strings in it. So it would check each row in a datagrid take from column 1 the find and use column 2 to replace then outputs the string to another txt file once the find and replace has taken place. My current results are that it just takes what was in the first file and copies without replacing in the second find.
Any assistance is gratefully received, many thanks.
Please see below my amateur code:-
Private Sub CmdBtnTestReplace_Click(sender As System.Object, e As System.EventArgs) Handles CmdBtnTestReplace.Click
Dim fName As String = "c:\backup\logs\masterUser.txt"
Dim wrtFile As String = "c:\backup\logs\masterUserFormatted.txt"
Dim strRead As New System.IO.StreamReader(fName)
Dim strWrite As New System.IO.StreamWriter(wrtFile)
Dim s As String
Dim o As String
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
Cursor.Current = Cursors.WaitCursor
s = strRead.ReadToEnd()
o = s.Replace(Find1, Replace1)
strWrite.Write(o)
End If
Next
strRead.Close()
strWrite.Close()
Cursor.Current = Cursors.Default
MessageBox.Show("Finished Replacing")
End Sub
1. What you are doing is :
creating a StreamReader whose purpose is to read chars from a File/Stream in sequence.
creating a StreamWriter whose purpose is to add content to a File/Stream.
then looping
a) read the remaining content of file fName and put it in s
b) replace words from s and put the result in o
c) add o to the existing content of the file wrtFile
then the usual closing of the stream reader/writer...
But that doesn't work because, on the secund iteration of the loop, strRead is already at the end of your loaded file, then there is nothing to read anymore, and s is always an empty string starting from the secund iteration.
Furthermore, because s is empty, o will be empty aswell.
And last of all, even if you manage to re-read the content of the file and replace the words, strWrite will not clear the initial content of the output file, but will write the resulting replaced string (o) after the previously updated content of the file.
2. Since you loaded the content of the file in a string (s = strRead.ReadToEnd()), why don't you :
load that s string before the For-Next block
loop the datagridview rows in a For-Next block
replace using the pair Find1/Replace1 s = s.Replace(Find1, Replace1)
then, save the content of s in the targeted file outside the For-Next block
3. However, improving your understanding of how streams work, what should be considered and what are forbidden is a bit outside the scope of SO I think; such documentation could be found/gathered on the MSDN page or with the help of your friend : google. The same applies for finding out/thinking of how you should arrange your code, how to achieve your goal.Let's take an example :
' Content of your file :
One Two Three Four Five Six
' Content of your DataGridView :
One | Two
Two | Three
Three | Four
Four | Five
Five | Six
Six | Seven
The resulting replacement text at the end of a similar routine as yours will be :
Seven Seven Seven Seven Seven Seven ' :/
' while the expected result would be :
Two Three Four Five Six Seven
And that's because of the iteration : already replaced portions of your file (or loaded file content) could get replaced again and again. To avoid that, either :
split the loaded content in single words, and use a "replaced" flag for each word (to avoid replacing that word more than once)
or preload all the pair Find/Replace, and parse the file content in sequence once, replacing that instance when required.
So, before using an interesting object in the framework :
you should know what it does and how it behaves
otherwise -> read the documentation
otherwise -> create a minimalistic test solution which purpose is to brute force testings on that particular object to debunck all its powers and flaws.
So, like I said in 2., move those ReadAllText() and Write() outside the For/Next block to start from and have a look at the resulting output (Ask specific questions in comments when google can't answer) Then if you're OK with it even if issue like the One Two Three example above could occur, then voila ! Otherwise, use google to gather more examples on "splitting text in words" and reformating the whole, have some tries, then get back here if you're stuck on precise issues.
I need your help, guys! :|
I've got myself a CSV file with the following contents:
1,The Compact,1.8GHz,1024MB,160GB,440
2,The Medium,2.4GHz,1024MB,180GB,500
3,The Workhorse,2.4GHz,2048MB,220GB,650
It's a list of computer systems, basically, that the user can purchase.
I need to read this file, line-by-line, into an array. Let's call this array csvline().
The first line of the text file would stored in csvline(0). Line two would be stored in csvline(1). And so on. (I've started with zero because that's where VB starts its arrays). A drop-down list would then enable the user to select 1, 2 or 3 (or however many lines/systems are stored in the file). Upon selecting a number - say, 1 - csvline(0) would be displayed inside a textbox (textbox1, let's say). If 2 was selected, csvline(1) would be displayed, and so on.
It's not the formatting I need help with, though; that's the easy part. I just need someone to help teach me how to read a CSV file line-by-line, putting each line into a string array - csvlines(count) - then increment count by one so that the next line is read into another slot.
So far, I've been able to paste the numbers of each system into an combobox:
Using csvfileparser As New Microsoft.VisualBasic.FileIO.TextFieldParser _
("F:\folder\programname\programname\bin\Debug\systems.csv")
Dim csvalue As String()
csvfileparser.TextFieldType = Microsoft.VisualBasic.FileIO.FieldType.Delimited
csvfileparser.Delimiters = New String() {","}
While Not csvfileparser.EndOfData
csvalue = csvfileparser.ReadFields()
combobox1.Items.Add(String.Format("{1}{0}", _
Environment.NewLine, _
csvalue(0)))
End While
End Using
But this only selects individual values. I need to figure out how selecting one of these numbers in the combobox can trigger textbox1 to be appended with just that line (I can handle the formatting, using the string.format stuff). If I try to do this using csvalue = csvtranslator.ReadLine , I get the following error message:
"Error 1 Value of type 'String' cannot be converted to '1-dimensional array of String'."
If I then put it as an array, ie: csvalue() = csvtranslator.ReadLine , I then get a different error message:
"Error 1 Number of indices is less than the number of dimensions of the indexed array."
What's the knack, guys? I've spent hours trying to figure this out.
Please go easy on me - and keep any responses ultra-simple for my newbie brain - I'm very new to all this programming malarkey and just starting out! :)
Structure systemstructure
Dim number As Byte
Dim name As String
Dim procspeed As String
Dim ram As String
Dim harddrive As String
Dim price As Integer
End Structure
Private Sub csvmanagement()
Dim systemspecs As New systemstructure
Using csvparser As New FileIO.TextFieldParser _
("F:\folder\programname\programname\bin\Debug\systems.csv")
Dim csvalue As String()
csvparser.TextFieldType = Microsoft.VisualBasic.FileIO.FieldType.Delimited
csvparser.Delimiters = New String() {","}
csvalue = csvparser.ReadFields()
systemspecs.number = csvalue(0)
systemspecs.name = csvalue(1)
systemspecs.procspeed = csvalue(2)
systemspecs.ram = csvalue(3)
systemspecs.harddrive = csvalue(4)
systemspecs.optical = csvalue(5)
systemspecs.graphics = csvalue(6)
systemspecs.audio = csvalue(7)
systemspecs.monitor = csvalue(8)
systemspecs.software = csvalue(9)
systemspecs.price = csvalue(10)
While Not csvparser.EndOfData
csvalue = csvparser.ReadFields()
systemlist.Items.Add(systemspecs)
End While
End Using
End Sub
Edit:
Thanks for your help guys, I've managed to solve the problem now.
It was merely a matter calling loops at the right point in time.
I would recommend using FileHelpers to do the reading.
The binding shouldn't be an issue after that.
Here is the Quickstart for Delimited Records:
Dim engine As New FileHelperEngine(GetType( Customer))
// To Read Use:
Dim res As Customer() = DirectCast(engine.ReadFile("FileIn.txt"), Customer())
// To Write Use:
engine.WriteFile("FileOut.txt", res)
When you get the file read, put it into a normal class and just bind to the class or use the list of items you have to do custom stuff with the combobox. Basically, get it out of the file and into a real class asap, then things will be easier.
At least take a look at the library. After using it, we use a lot more simple flat files since it is so easy, and we haven't written a file access routine since (for that kinda stuff).
http://msdn.microsoft.com/en-us/library/microsoft.visualbasic.fileio.textfieldparser.aspx
I think your main problem is understanding how arrays work (hence the error message).
You can use split and join functions to convert strings into and out of arrays
dim s() as string = split("1,2,3",",") gives and array of strings with 3 elements
dim ss as string = join(s,",") gives you the string back
Firstly, it's actually really good that you are using the TextFieldParser for reading CSV files - most don't but you won't have to worry about extra commas and quoted text etc...
The Readline method only gives you the raw string, hence the "Error 1 Value of type 'String' cannot be converted to '1-dimensional array of String'."
What you may find easier with combo boxes etc is to use an object (e.g. 'systemspecs') rather than strings. Assign the CSV data to the objects and override the "ToString" method of the 'systemspecs' class to display in the combo box how you want with formatting etc. That way when you handle the SelectedIndexChanged event (or similar) you get the "SelectedItem" from the combo box (which can be Nothing so check) and cast it as the 'systemspecs' to use it. The advantage is that you are not restricted to display the exact data in the combo etc.
' in "systemspecs"...
Public Overrides Function ToString() As String
Return Name ' or whatever...
End Function ' ToString
e.g.
dim item as new systemspecs
item.ID = csvalue(1)
item.Name = csvalue(2)
' etc...
combobox1.Items.Add(item)
Let me know if that makes sense!
PK :-)