Hello people as the topic show I want to do in VB.net a script that gets only the numbers from a *.txt file
EXAMPLE:
text file:
asd4lkj5fdl
jklj235
the result:
45235
I have done a research in Google and come up with nothing, I did saw a answer here but only in C
I know that in theory it needs to be like this:
Read every char loop ask if it is an integer add it to a new string if not continue to next char do this till the end of the stream
Thanks for the one how helps !
Try regular expressions, code to read text from file is no included
Dim rgx As New Regex("[^\d]")
Dim result as String = rgx.Replace("asd4lkj5fdl jklj235", "")
Read File into a String
Loop through each char checking if numeric.
Dim strTextFromFile As String = IO.File.ReadAllText("C:\filename.txt")
Dim strResults As String = String.Empty
For Each c As Char In strTextFromFile
If IsNumeric(c) Then
strResults += c
End If
Next
MsgBox(strResults)
Public Sub Test()
Dim contents As String = File.ReadAllText("C:\\temp\\text.txt")
Dim digits As New String(contents.Where(Function(c) Char.IsDigit(c)).ToArray())
MessageBox.Show(digits)
End Sub
Related
This is the first challenge on Day 1 of the 2018 Advent of Code
(link: https://adventofcode.com/2018/day/1)
So I am trying to create a program that reads a long list of positive and negative numbers (e.g +1, -2, +3, etc.) and then add them up to create a total. I have researched some methods of file handling in Visual Basic, and have come up with the below method:
Sub Main()
Dim objStreamReader As StreamReader
Dim strLine As String = ""
Dim total As Double = 0
objStreamReader = New StreamReader(AppDomain.CurrentDomain.BaseDirectory & "frequencies.txt")
strLine = objStreamReader.ReadLine
Do While Not strLine Is Nothing
Console.WriteLine(strLine)
strLine = objStreamReader.ReadLine
total += strLine
Loop
Console.WriteLine(total)
objStreamReader.Close()
Console.ReadLine()
End Sub
Here is a link to the list of numbers: https://adventofcode.com/2018/day/1/input
It is not a syntax error I am getting but a logic error. The answer is somehow wrong, but I cannot seem to figure out where! I have tried to remove the signs from each number but that throws me a NullException error when it compiles.
So far I have come out with the answer 549, which the Advent of Code webiste rejects. Any ideas?
Make your life easier by using File.ReadLines(fileName) instead of dealing with StreamReader. Use Path.Combine instead of string concatenation to create a path. Path.Combine takes care of adding missing \ or removing extra ones etc.
Your file might contain an extra empty line at its end, that does not convert to a number. Use Double.TryParse to make sure you have a valid number before totalizing it. You should have Option Strict On anyway to enforce explicit conversions.
Dim fileName = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "frequencies.txt")
Dim total As Double = 0
For Each strLine As String In File.ReadLines(fileName)
Console.WriteLine(strLine)
Dim n As Double
If Double.TryParse(strLine, n) Then
total += n
End If
Next
Console.WriteLine(total)
Console.ReadLine()
For appending two string, please use string builder.
Dim test as new stringbuilder()
Test.append("your string")
It will not affect performance.
I want to calculate the number of words in a text file using a delimiter of a space (" "), however I am struggling.
Dim counter = 0
Dim delim = " "
Dim fields() As String
fields = Nothing
Dim line As String
line = Input
While (SR.EndOfStream)
line = SR.ReadLine()
End While
Console.WriteLine(vbLf & "Reading File.. ")
fields = line.Split(delim.ToCharArray())
For i = 0 To fields.Length
counter = counter + 1
Next
SR.Close()
Console.WriteLine(vbLf & "The word count is {0}", counter)
I do not know how to open the file and to get the do this, very confused; would like an explanation so I can edit and understand from it.
You're going to be reading a file as the source of the data, so let's create a variable to refer to its filename:
Dim srcFile = "C:\temp\twolines.txt"
As you have shown already, a variable is needed to hold the number of words found:
Dim counter = 0
To read from the file, a StreamReader will do the job. Now, we look at the documenation for it (yes, really) and notice that it has a Dispose method. That means that we have to explicitly dispose of it after we've used it to make sure that no system resources are tied up until the computer is next rebooted (e.g there could be a "memory leak"). Fortunately, there is the Using construct to take care of that for us:
Using sr As New StreamReader(srcFile)
And now we want to iterate over the content of the file line-by-line until the end of the file:
While Not sr.EndOfStream
Then we want to read a line and find how many items separated by spaces it has:
counter += sr.ReadLine().Split({" "c}, StringSplitOptions.RemoveEmptyEntries).Length
The += operator is like saying "add n to a" instead of saying "a = a + n". The {" "c} is a literal array of the character " "c. The c tells it that is a character and not a string of one character. The StringSplitOptions.RemoveEmptyEntries means that if there was text of "one two" then it would ignore the extra spaces.
So, if you were writing a console program, it might look like:
Imports System.IO
Module Module1
Sub Main()
Dim srcFile = "C:\temp\twolines.txt"
Dim counter = 0
Using sr As New StreamReader(srcFile)
While Not sr.EndOfStream
counter += sr.ReadLine().Split({" "c}, StringSplitOptions.RemoveEmptyEntries).Length
End While
End Using
Console.WriteLine(counter)
Console.ReadLine()
End Sub
End Module
Any embellishments such as writing out what the number represents or error checking are left up to you.
With Path.Combine you don't have to worry about where the slashes or back slashes go. You can get the path of special folders easily using the Environment class. The File class of System.IO is shared so you don't have to create an instance.
Public Sub Main()
Dim p As String = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments), "Chapters.txt")
Debug.Print(Environment.SpecialFolder.MyDocuments.ToString)
Dim count As Integer = GetCount(p)
Console.WriteLine(count)
Console.ReadKey()
End Sub
Private Function GetCount(Path As String) As Integer
Dim s = File.ReadAllText(Path)
Return s.Split().Length
End Function
Use Split function, then Directly get the length of result array and add 1 to it.
I'm beginner with VB.net.
How do I read indexes for certain character in a string? I read an barcode and I get string like this one:
3XXX123456-C-AA123456TY-667
From that code I should read indexes for character "-" so I can cut the string in parts later in the code.
For example code above:
3456-C
6TY-667
The length of the string can change (+/- 3 characters). Also the places and count of the hyphens may vary.
So, I'm looking for code which gives me count and position of the hyphens.
Thanks in advance!
Use the String.Splt method.
'a test string
Dim BCstring As String = "3XXX123456-C-AA123456TY-667"
'split the string, removing the hyphens
Dim BCflds() As String = BCstring.Split({"-"c}, StringSplitOptions.None)
'number of hyphens in the string
Dim hyphCT As Integer = BCflds.Length - 1
'look in the debuggers immediate window
Debug.WriteLine(BCstring)
'show each field
For Each s As String In BCflds
Debug.WriteLine(String.Format("{0,5} {1}", s.Length, s))
Next
'or
Debug.WriteLine(BCstring)
For idx As Integer = 0 To hyphCT
Debug.WriteLine(String.Format("{0,5} {1}", BCflds(idx).Length, BCflds(idx)))
Next
If all you need are the parts between hyphens then as suggested by dbasnett use the split method for strings. If by chance you need to know the index positions of the hyphens you can use the first example using Lambda to get the positions which in turn the count give you how many hyphens were located in the string.
When first starting out with .NET it's a good idea to explore the various classes for strings and numerics as there are so many things that some might not expect to find that makes coding easier.
Dim barCode As String = "3XXX123456-C-AA123456TY-667"
Dim items = barCode _
.Select(Function(c, i) New With {.Character = c, .Index = i}) _
.Where(Function(item) item.Character = "-"c) _
.ToList
Dim hyphenCount As Integer = items.Count
Console.WriteLine("hyphen count is {0}", hyphenCount)
Console.WriteLine("Indices")
For Each item In items
Console.WriteLine(" {0}", item.Index)
Next
Console.WriteLine()
Console.WriteLine("Using split")
Dim barCodeParts As String() = barCode.Split("-"c)
For Each code As String In barCodeParts
Console.WriteLine(code)
Next
Here is an example that'll split your string and allow you to parse through the values.
Private Sub TestSplits2Button_Click(sender As Object, e As EventArgs) Handles TestSplits2Button.Click
Try
Dim testString As String = "3XXX123456-C-AA123456TY-667"
Dim vals() As String = testString.Split(Convert.ToChar("-"))
Dim numberOfValues As Integer = vals.GetUpperBound(0)
For Each testVal As String In vals
Debug.Print(testVal)
Next
Catch ex As Exception
MessageBox.Show(String.Concat("An error occurred: ", ex.Message))
End Try
End Sub
I am trying to search a text document, and I am at a stand still.
Example of the document:
11/24 05:05:21.781 T0EA8 [PinRegister Version: PINREG 1.2.0]
11/24 05:05:21.875 T0EA8 [RequestPinPadParamEvent: PR_RegDevice = 0.Exit]
11/25 05:04:38.906 T0FB0 [*************************: ]
11/25 05:04:38.906 T0FB0 [PinRegister Version: PINREG 1.3.0]
Now, in that example document, I want to display the 'PinPegister Version' to textbox 'VersionTextBox' from the 25th.
So I am trying to search for the date, then from the date search for the phrase ('[PinRegister Version: ]') and finaly display the results into the textbox ('PINREG 1.3.0').
I have tried alot of options, with nothing working how I want it.
This is my current code, and I feel close... but I am getting an error 'Object reference not set to an instance of an object.'
Dim strm As IO.Stream = IO.File.OpenRead(fpath)
Dim sr As New IO.StreamReader(strm)
Dim line As String
Dim trimchars() As Char = {" "c}
Dim datelist As ArrayList
Do While sr.Peek <> -1
line = sr.ReadLine()
'If line.TrimStart(trimchars).Contains("[PinRegister Pin Pad Model") Then
If line.TrimStart(trimchars).StartsWith(TDate.Text) Then
' found pattern
datelist.Add(line)
End If
Loop
If datelist.Contains("PinRegister Version:") Then
MsgBox("Found 1")
End If
Thanks in advance for any help
Couldn't you just do something like this?
Public Shared Sub FindStuff()
Dim TextFileLocation = "C:\Test\Test.txt"
Dim srReader As IO.StreamReader = Nothing
srReader = File.OpenText(TextFileLocation)
Do
Dim strInputFileLine As String = srReader.ReadLine()
If strInputFileLine Is Nothing Then Exit Do
If strInputFileLine.Contains(Form1.TextBox1.Text) Then
MessageBox.Show("Found it")
End If
Loop
You didn't say how big your input file is, but if its not too large I would suggest reading in all into a string
My.Computer.FileSystem.ReadAllText
and then using a
yourstring.indexof( ...
to find the text you are looking for and work it from there.
I've done this in the past and its quite fast in most cases.
I'm trying to delete a selected row, then save the rest into a file. However, when I save it, it totally empties the file.
Console.Write("Please eneter the first name of the student you wish to search for: ")
searchfname = Console.ReadLine
searchfname = StrConv(searchfname, VbStrConv.ProperCase)
Console.Write("Please enter the second name of the student you wish to search for: ")
searchsname = Console.ReadLine
searchsname = StrConv(searchsname, VbStrConv.ProperCase)
Dim foundItem() As String = Nothing
Dim foundline As String = Nothing
Dim fnsearch As String = String.Join(searchfname, searchsname)
Dim lines As New List(Of String)(File.ReadAllLines("F:\Computing\Spelling Bee\stdnt&staffdtls.csv"))
For Each line As String In lines
If searchfname = item(3) And searchsname = item(4) Then
Console.WriteLine(line)
Console.WriteLine()
Console.WriteLine("Are you sure you wish to delete this record? (y/n)")
End If
Dim answer As String
answer = Console.ReadLine
If answer = "y" Or answer = "Y" Then
Console.Clear()
lines.Remove(line)
Using sw As New StreamWriter("F:\Computing\Spelling Bee\stdnt&staffdtls.csv")
sw.WriteLine(lines.ToString)
End Using
ElseIf answer = "n" Or answer = "N" Then
staffmenu()
End If
Next
Look at this line in your code:
sw.WriteLine(lines.ToString)
Extract the lines.ToString expression from that statement. The result of that expression is "System.String". You are telling your stream writer to write the text "System.String" to the file.
To fix it, you need something more like this:
Using sw As New StreamWriter("F:\Computing\Spelling Bee\stdnt&staffdtls.csv")
For Each line As String In lines
sw.WriteLine(line)
Next line
End Using
The method List(Of T).ToString does not produce a value that includes the elements of the collection. Instead it will just return the type name.
The API you are looking for is File.WriteAllLines. Using this instead of StreamWriter and the Using block
File.WriteAllLines("F:\Computing\Spelling Bee\stdnt&staffdtls.csv", lines)
I can see that this issue can be resolved from the given answers and comment, but I would like to add an alternative to use Join function in writing to a file. Try like this may be of help:
Using sw As New StreamWriter(.....)
sw.WriteLine(Join(lines.ToArray(), Environment.NewLine))
End Using
Since using VB.Net, this is a vb.net specific solution can not be used in C#. For C#, use string.join instead.
Hope it helps too!