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.
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
start=AKS-RHzlSXSftLGYdBNk.eyJhbGdvcml0aG0iOiJITUFDLVNIQTI1&
For every instance of the word 'start' I need to be able to get the text after the first full stop, right up until the & symbol. E.g. 'eyJhbGdvcml0aG0iOiJITUFDLVNIQTI1'.
There will be more than one instance of this. They will need to be appended to a listbox.
What is the simplest/quickest way to do this? (Using possibly streamreader - text file)
The simplest and quickest way will be to read each line, and check if it .StartsWith("start="). If so, then get the .IndexOf(".") and the .IndexOf("&", <whereever the first indexOf was>). Get the .SubString which encompasses those two values. I'm sure you can write the code yourself from that ;)
I tested this function with a button click, output text each line on a textbox. I am sure you can adapt this to your code.
Private Sub Button_Click(sender As Object, e As RoutedEventArgs)
txtResults.Text = ""
Dim ParseString As String
ParseString = "start=123341.23124&kjdshfkjsdaksdstart=1231.2321312&kadhskjashdkjastart=1231.23126789898&skjdfhkjsd"
Dim Delimiters() As String = New String() {"start="}
Dim Words() As String
Words = ParseString.Split(Delimiters, CompareMethod.Text)
For Each Part In Words
Dim Middle As String
Middle = Part.Split(".").Skip(1).Take(1).FirstOrDefault()
Dim Good As String
Good = Middle.Split("&").FirstOrDefault()
txtResults.Text += Good + vbNewLine
Next
End Sub
Output was
23124
2321312
23126789898
Added 31104 lines to a string and ran, took about 11 seconds to run on my laptop. Might be too slow for your app?
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.
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.
i am trying to split a string up into separate lines with the following code, but for some reason it is also removing the spaces in the string.
Dim calculationText As String
calculationText = File.ReadAllText(fileName)
Dim fields() As String
fields = calculationText.Split(vbCrLf)
when i am in debugger mode, i look at fields, and every element has a line of the string but all the spaces and tabs are removed.
any reason for this?
If you are reading from a file, can you use:
Sub Main()
Dim fields As New List(Of String)
' read file into list
Using sr As System.IO.StreamReader = My.Computer.FileSystem.OpenTextFileReader(filename)
Try
Do While sr.Peek() >= 0
fields.Add(sr.ReadLine())
Loop
Finally
If sr IsNot Nothing Then sr.Close()
End Try
End Using
' check results
For Each line As String In fields
Console.WriteLine(line)
Next
End Sub
How 'bout:
Dim fields() As String = File.ReadAllLines(fileName)
As for why string.Split() is doing weird things...
vbCrLf is a string, and there's not an overload for string.split that accepts a single string parameter. If he were to turn on Option Explicit it wouldn't even compile, but since it's off, vbCrLf can be interpreted as an array of characters. And in this code, that's exactly what happens:
Sub Main()
Dim z As String = "The quick brown" & vbCrLf & " fox jumps over the lazy dogs."
Dim a() As String = z.Split(vbCrLf)
For Each c As String In a
Console.WriteLine(c)
Next
Console.ReadKey(True)
End Sub
You'll see two line breaks between the 1st and 2nd parts of that string. Something else is stripping out the spaces. Can you share the larger code block?
Gotta say I've never seen it do that, and I've used String.Split extensively. Are they really really gone, or is it a trick of the debugger?
There's not actually any .Split method that takes one string as the parameter, so the VB compiler would be doing "things" behind the scenes to pick a different overload. To try and force the correct overload, you could try calculationText.Split(vbCrLf.ToCharArray()). I doubt it will help, but you never know :-)