What I have:
So there is this large project I'm working on for school, and I have everything working except for a small but vital piece. The programm I am working on must convert currency, and take the rates from a txt file. The file looks like this:
USD 1,2694
JPY 100,44
BGN 1,955
CZK 25,396
DKK 7,45792
...
There is a tab break between the name and the value and a line break between the value and the next currency name. Values have a floating point, and don't have a fixed length.
What I need:
I need to break this string into two arrays, currencyNames() and currencyValues(), or into a two-dimentional array currency().
What I can do myself:
I can load it from a file into a string with
fileReader = My.Computer.FileSystem.ReadAllText("rates.txt")
And I was able to break it into an array with a simple loop
Do While i < 32
dummyArray = Split(fileReader, " ")
i += 1
Loop
but only when there is a space separating the names and values inside the file.
What you're looking for are the VB Constants, a set of special strings for special characters like tab and new line - there's a list at the link, but yours in particular are vbTab and vbCrLf. You shouldn't need to import anything - they're built in to VB.
To use them, you'd change it to something like:
dummyArray = Split(fileReader, vbCrLf) ' to split on lines
And then:
For Each s as String In dummyArray
otherArray = Split(s, vbTab) ' to split on tab characters
The basic idea is something like this:
Read each line from the file
Split the line on the space bar
Store the Country as the first portion of the split
Store the amount as the second portion, formatted as an integer
Project the Country and Amount into seperate arrays
Here's a simple implementation in Vb.Net
Sub Main
dim input = System.IO.File.ReadAllLines("c:\yourdata.txt")
dim projection = from line in input
let split = line.Split(new string(){" "},StringSplitOptions.RemoveEmptyEntries)
select Country = split.First(), Amount = split.Last().Replace(",","").Parse()
dim countries = projection.Select(function(p) p.Country).ToArray()
dim amounts = projection.Select(function(p) p.Amount).ToArray()
End Sub
I also used a small extension method to wrap Integer.TryParse
namespace ExtensionMethods
public module Extensions
<Extension()>_
public function Parse(byval value as string) as integer
dim i = 0
if integer.TryParse(value,out i) then
return i
end if
return 0
end function
end module
end namespace
A combination of ReadLine() and String.Split() should help you solve your problem.
If you were to a read each item line by line, using ReadLine(), you could then split on the space like this:
ReadLine().Split(' ').First();
and
ReadLine().Split(' ').Last();
to get the relevant values from your pair.
Related
I have a question which asks me to calculate something from an input file. The problem is, the lines in the file don't use any special character as delimiter, like , or |. I will show it down below.
Data Communication
20
Visual Basic
40
The output I need to write to another file should look like this:
Data communication 20
Visual Basic 40
Total Books : 60
The problem is, how can I specify the delimiter? Like when there is a symbol as in strArray = strLine.Split(","). Since there is nothing I can use as delimiter, how can I split the file content?
There's no real need to split the text in the input file, when you can read a file line by line using standard methods.
You can use, e.g., a StreamReader to read the lines from the source file, check whether the current line is just text or it can be converted to a number, using Integer.TryParse and excluding empty lines.
Here, when the line read is not numeric, it's added as a Key in a Dictionary(Of String, Integer), unless it already exists (to handle duplicate categories in the source file).
If the line represents a number, it's added to the Value corresponding to the category Key previously read, stored in a variable named previousLine.
This setup can handle initial empty lines, empty lines in the text body and duplicate categories, e.g.,
Data Communication
20
Visual Basic
40
C#
100
Visual Basic
10
Other stuff
2
C++
10000
Other stuff
1
If a number is instead found in the first line, it's treated as a category.
Add any other check to handle a different structure of the input file.
Imports System.IO
Imports System.Linq
Dim basePath = "[Path where the input file is stored]"
Dim booksDict = New Dictionary(Of String, Integer)
Dim currentValue As Integer = 0
Dim previousLine As String = String.Empty
Using sr As New StreamReader(Path.Combine(basePath, "Books.txt"))
While sr.Peek > -1
Dim line = sr.ReadLine().Trim()
If Not String.IsNullOrEmpty(line) Then
If Integer.TryParse(line, currentValue) AndAlso (Not String.IsNullOrEmpty(previousLine)) Then
booksDict(previousLine) += currentValue
Else
If Not booksDict.ContainsKey(line) Then
booksDict.Add(line, 0)
End If
End If
End If
previousLine = line
End While
End Using
Now, you have a Dictionary where the Keys represent categories and the related Value is the sum of all books in that category.
You can Select() each KeyValuePair of the Dictionary and transform it into a string that represents the Key and its Value (Category:Number).
Here, also OrderBy() is used, to order the categories alphabetically, in ascending order; it may be useful.
File.WriteAllLines is then called to store the strings generated.
In the end, a new string is appended to the file, using File.AppendAllText, to write the sum of all books in all categories. The Sum() method sums all the Values in the Dictionary.
Dim newFilePath = Path.Combine(basePath, "BooksNew.txt")
File.WriteAllLines(newFilePath, booksDict.
Select(Function(kvp) $"{kvp.Key}:{kvp.Value}").OrderBy(Function(s) s))
File.AppendAllText(newFilePath, vbCrLf & "Total Books: " & booksDict.Sum(Function(kvp) kvp.Value).ToString())
The output is:
C#:100
C++:10000
Data Communication:20
Other stuff:3
Visual Basic:50
Total Books: 10173
Sure.. System.IO.File.ReadAllLines() will read the whole file and split into an array based on newlines, so you'll get an array of 4 elements. You can process it with a flipflop boolean to get alternate lines, or you can try and parse the line to a number and if it works, then its a number and if not, it's a string. If it's a number take the string you remembered (using a variable) from the previous loop
Dim arr = File.ReadALlLines(...)
Dim isStr = True
Dim prevString = ""
For Each s as String in arr
If isStr Then
prevString = s
Else
Console.WriteLine($"The string is {prevString} and the number is {s}")
End If
'flip the boolean
isStr = Not isStr
Next s
I used File.ReadAllLines to get an array containing each line in the file. Since the size of the file could be larger than the sample shown, I am using a StringBuilder. This save having to throw away and create a new string on each iteration of the loop.
I am using interpolated strings indicated by the $ preceding the quotes. This allows you to insert variables into the string surrounded by braces.
Note the Step 2 in the For loop. i will increment by 2 instead of the default 1.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim lines = File.ReadAllLines("input.txt")
Dim sb As New StringBuilder
Dim total As Integer
For i = 0 To lines.Length - 2 Step 2
sb.AppendLine($"{lines(i)} {lines(i + 1)}")
total += CInt(lines(i + 1))
Next
sb.AppendLine($"Total Books: {total}")
TextBox1.Text = sb.ToString
End Sub
Does anybody know how to lowercase the first word for each line in a textbox?
Not the first letter, the first word.
I tried like this but it doesn't work:
For Each iz As String In txtCode.Text.Substring(0, txtCode.Text.IndexOf(" "))
iz = LCase(iz)
Next
When you call Substring, it is making a copy of that portion of the string and returning it as a new string object. So, even if you were successfully changing the value of that returned sub-string, it still would not change the original string in the Text property.
However, strings in .NET are immutable reference-types, so when you set iz = ... all you are doing is re-assigning the iz variable to point to yet another new string object. When you set iz, you aren't even touching the value of that copied sub-string to which it previously pointed.
In order to change the value of the text box, you must actually assign a new string value to its Text property, like this:
txtCode.Text = "the new value"
Since that is the case, I would recommend building a new string, using a StringBuilder object, and then, once the modified string is complete, then set the text box's Text property to that new string, for instance:
Dim builder As New StringBuilder()
For Each line As String In txtCode.Text.Split({Environment.NewLine}, StringSplitOptions.None)
' Fix case and append line to builder
Next
txtCode.Text = builder.ToString()
The solutions here are interesting but they are ignoring a fundamental tool of .NET: regular expressions. The solution can be written in one expression:
Dim result = Regex.Replace(txtCode.Text, "^\w+",
Function (match) match.Value.ToLower(), RegexOptions.Multiline)
(This requires the import System.Text.RegularExpressions.)
This solution is likely more efficient than all the other solutions here (It’s definitely more efficient than most), and it’s less code, thus less chance of a bug and easier to understand and to maintain.
The problem with your code is that you are running the loop only on each character of the first word in the whole TextBox text.
This code is looping over each line and takes the first word:
For Each line As String In txtCode.Text.Split(Environment.NewLine)
line = line.Trim().ToLower()
If line.IndexOf(" ") > 0 Then
line = line.Substring(0, line.IndexOf(" ")).Trim()
End If
// do something with 'line' here
Next
Loop through each of the lines of the textbox, splitting all of the words in the line, making sure to .ToLower() the first word:
Dim strResults As String = String.Empty
For Each strLine As String In IO.File.ReadAllText("C:\Test\StackFlow.txt").Split(ControlChars.NewLine)
Dim lstWords As List(Of String) = strLine.Split(" ").ToList()
If Not lstWords Is Nothing Then
strResults += lstWords(0).ToLower()
If lstWords.Count > 1 Then
For intCursor As Integer = 1 To (lstWords.Count - 1)
strResults += " " & lstWords(intCursor)
Next
End If
End If
Next
I used your ideas guys and i made it up to it like this:
For Each line As String In txtCode.Text.Split(Environment.NewLine)
Dim abc() As String = line.Split(" ")
txtCode.Text = txtCode.Text.Replace(abc(0), LCase(abc(0)))
Next
It works like this. Thank you all.
I have a continuous string of words coming from a machine to hyper terminal of my system, for which I am using USB to serial cable. I want to find some of the values which comes after a specific word in that string and then store it.
I used threads and splitting concepts to do it but as per the requirement and operation of the machine it will not work properly in the runtime.
The values which I want to capture comes from a specific word. I want to skip that words and just store the values. How to do it?
I have given the example of that string below:
MEAN 49 50
SD 500 10
MIN 100 5
MAX 50 45.56
In this I just want to store the values e.g. 49 and 50, then discard MEAN. Then discard SD and store 500 and 10 and so on.
You can use a StreamReader object to read the stream one line at a time. Then, you can easily parse the line using the String.Split method. I would recommend creating one or more classes that represent the data being read, like this:
Public Class LineData
Public Property Label As String
Public Property Value1 As Decimal
Public Property Value2 As Decimal
End Class
Public Function ReadNextLine(stream As Stream) As LineData
Dim reader As New StreamReader(stream)
Dim line As String = reader.ReadLine()
Dim data As LineData = Nothing
If line IsNot Nothing Then
Dim words() As String = line.Split(New Char() {" "c}, StringSplitOptions.RemoveEmptyEntries)
If words.Length = 3 Then
data = New LineData()
data.Label = words(0)
data.Value1 = Decimal.Parse(words(1))
data.Value2 = Decimal.Parse(words(2))
End If
End If
Return Data
End Function
Note, this is a very simple example based on the example data you provided. If different lines have different numbers of numeric parameters, that will further complicate the logic. In my example, the method returns Nothing if no data can be read. Also, the method will throw an exception if the last two words in the line are not numeric. Therefore, you would need to wrap it in some additional exception handling.
This may be what you're looking for. Although personally I'd create a class which stores the type(mean, median etc), firstvalue and secondvalue.
By the sounds of it though, all you want it to do is dump the values into some sort of storage, therefore this will suffice.
Dim Values as New List(Of Decimal)
'Use a streamreader to read each line of text
Using reader As StreamReader = New StreamReader(*your text source*)
'Read the line
Dim linetext as string = reader.ReadLine
Dim myValue as decimal
'Split the line
Dim splitText() = linetext.Split(" ")
'Analyze each section of the line, if its possible to parse the value as a decimal then add it to the list of values to be stored.
For Each txt in splitText
If Decimal.TryParse(txt, myValue) then Values.Add(myValue)
Next
End Using
I have an application which creates a list from items in a collection. Then for each item, I will add it to an empty string, then add a newline character to the end of it. So ideally my string will look something like:
List1\nList2\nList3\n
Once this string is generated, I send it back to be placed in a placeholder for a pdf. If I try this code in a simple console application, it prints everything on a newline. But in my real world situation, I have to print it to a pdf. The items only show up with spaces in between them and not newlines. How can can format my strings so that pdf recognizes the newline symbol rather than ignoring it?
Here is my code that generates the string with newlines.
Private Function ConcatPlacardNumbers(ByVal BusinessPlacardCollection As BusinessPlacardCollection) As String
Dim PlacardNumbersList As String = Nothing
Dim numberofBusinessPlacards As Long = BusinessPlacardCollection.LongCount()
For Each BusinessPlacard As BusinessPlacard In BusinessPlacardCollection
numberofBusinessPlacards = numberofBusinessPlacards - 1
PlacardNumbersList = String.Concat(PlacardNumbersList, BusinessPlacard.PlacardNumber)
If numberofBusinessPlacards <> 0 Then
PlacardNumbersList = String.Concat(PlacardNumbersList, Enviornment.newline)
End If
Next
Return PlacardNumbersList
End Function
Try to add \u2028 instead:
Private Function ConcatPlacardNumbers(ByVal BusinessPlacardCollection As _
BusinessPlacardCollection) As String
Dim PlacardNumbersList As New StringBuilder()
For Each BusinessPlacard As BusinessPlacard In BusinessPlacardCollection
PlacardNumbersList.Append(BusinessPlacard.PlacardNumber)
'PlacardNumbersList.Append(ChrW(8232)) '\u2028 line in decimal form
PlacardNumbersList.Append(ChrW(8233)) '\u2029 paragr. in decimal form
Next
Return PlacardNumbersList.ToString
End Function
For paragraphs use \u2029instead. Fore more details:
http://blogs.adobe.com/formfeed/2009/01/paragraph_breaks_in_plain_text.html
The answer will depend on the tool that is being used to produce the PDF. Since newline doesn't work, I would actually try \n. The other possibility is that the PDF generation code is not designed to emit multiple lines; you can only determine this by examining the generation code.
However, there is a significant performance issue that you should address in your code: you will be generating a lot of string objects using this code. You should change the design to use System.Text.StringBuilder, which will greatly improve the performance:
Private Function ConcatPlacardNumbers(ByVal BusinessPlacardCollection As BusinessPlacardCollection) As String
Dim PlacardNumbersList As New System.Text.StringBuilder(10000)
For Each BusinessPlacard As BusinessPlacard In BusinessPlacardCollection
If PlacardNumbersList.Length <> 0 Then
' This is equivalent to Environment.NewLine
'PlacardNumbersList.AppendLine()
' The attempt to use \n
PlacardNumbersList.Append("\n")
End If
PlacardNumbersList.Append(BusinessPlacard.PlacardNumber)
Next
Return PlacardNumbersList.ToString
End Function
Note that you also do not need to keep track of the placard number: you can add a newline to the end of the previous item on each pass after the first one.
My request is one that can extract a number somewhat by a search.
Example:
animalsOwned|4 would return an containing "4"
animals|3|2|1|3 would return an array containing "3", "2", "1", "3"
This would make it easier for me during a file stream reader.
Thank you
Dim astring = "ABCDE|1|2|3|4"
Dim numbers = (From s In astring
Where Char.IsDigit(s)
Select Int32.Parse(s)).ToArray()
This LINQ statement should help. It simply checks each character in a string to see if it's a digit. Note that this only applies to single digit numbers. It becomes a bit more complicated if you want "ABC123" to return 123 vs. 1, 2, 3 array.
Try regular expression. It's a powerful tool for simple text parsing.
Imports System.Text.RegularExpressions
Namespace Demo
Class Program
Shared Function Main(ByVal args As String()) As Integer
Dim array As Integer() = ExtractIntegers("animals|3|2|1|3")
For Each i In array
Console.WriteLine(i)
Next
Return 0
End Function
Shared Function ExtractIntegers(ByVal input As String) As Integer()
Dim pattern As String = "animals(\|(?<number>[0-9]+))*"
Dim match As Match = Regex.Match(input, pattern)
Dim list As New List(Of Integer)
If match.Success Then
For Each capture As Capture In match.Groups("number").Captures
list.Add(Integer.Parse(capture.Value))
Next
End If
Return list.ToArray()
End Function
End Class
End Namespace
I haven't programmed VB for awhile but I'll give you some pseudo code:
First, loop through each line of file. Call this variable Line.
Then, take the index of what you're searching for: like Line.indexOf("animalsOwned")
If it returns -1 it isn't there; continue.
Once you find it, add the Index variable to the length of the search string and 1. (Index=Index+1+Len(searchString))
Then, take a substring starting there, and end at the end of the line.
Explode the substring by | characters, then add each into an array.
Return the array.
Sorry that I can't give you much help, but I'm working on an important PHP website right now ;).
You can do a variable.Split("|") and then assign each piece to an array level.
You can do a count on string and with a while or for loop, you can assign the splited sections to array levels. Then you can do a IsNumeric() check for each array level.