I have a small problem for which I need help.
I have a webbrowser, and a button that finds a text from a class, well heres the code below:
Dim word As String = (WebBrowser1.Document.GetElementsByTagName("P").Cast(Of HtmlElement) _
.FirstOrDefault(Function(el) el.GetAttribute("className") = "tagline").InnerText)
Dim lastWord As String = word.Split(" ").Last
If Not ListBox1.Items.Contains(lastWord) Then
ListBox1.Items.Add(lastWord)
End If
The site has multible classes with the name "tagline", and I want the button to get the next one after I press it.
How can I do this..?
You need to have a global variable that keeps the index of the "tagline" that you want to retrieve. And use this indexer as a parameter for the Skip method to apply to the sequence returned by a Where instead of FirstOrDefault
' Declared at the global level
Dim index as Integer = 0
' At each button press you write
Dim word As String = WebBrowser1.Document.GetElementsByTagName("P") _
.Cast(Of HtmlElement) _
.Where(Function(el) el.GetAttribute("className") = "tagline") _
.Skip(index) _
.First().InnerText
Dim lastWord As String = word.Split(" ").Last
index = index + 1
So at the next button press you skip to the second element then to third and so on. However this poses a problem. You should know how many elements are present in your WebBrowser Document to avoid requesting an inexistant element. So perhaps it is better to get all the elements with the "tagline" attribute and keep them in a list where they can be easily retrieved
' Declared at the global level
Dim index as Integer = 0
Dim elements = new List(Of HtmlElement)()
' After you have loaded the document
elements = WebBrowser1.Document.GetElementsByTagName("P") _
.Cast(Of HtmlElement) _
.Where(Function(el) _
el.GetAttribute("className") = "tagline") _
.ToList()
and in the button code just
if index < elements.Count Then
Dim word = elements.Skip(index).First().InnerText
Dim lastWord As String = word.Split(" ").Last
index = index + 1
End if
Related
Recently I've encountered a rather odd dictionary behaviour.
Sub DictTest()
Dim iDict As Object
Dim i As Integer
Dim strArr() As String
Set iDict = CreateObject("Scripting.Dictionary")
strArr = Split("Why does this happen ? Why does this happen over and over ?", " ")
For i = LBound(strArr) To UBound(strArr)
iDict(strArr(i)) = strArr(i)
Next
End Sub
The output is iDict populated with 7 items:
But whenever I add watch:
It adds an empty item to a dictionary:
Why does adding a watch expression create an empty item in the dictionary?
If you examine the entry in the dictionary with a key of "What???" then naturally an entry must be created in the dictionary in order to show you that entry.
If you want to just check whether an entry exists, then perform a watch on iDict.Exists("What???").
Adding a watch is operating no differently to the following code:
Sub DictTest()
Dim iDict As Object
Dim i As Integer
Dim strArr() As String
Set iDict = CreateObject("Scripting.Dictionary")
strArr = Split("Why does this happen ? Why does this happen over and over ?", " ")
For i = LBound(strArr) To UBound(strArr)
iDict(strArr(i)) = strArr(i)
Next
MsgBox "The value of the 'What???' entry in iDict is '" & iDict("What???") & "'"
End Sub
This changing of the contents of a Dictionary object is no different to using the Watch Window to change the value of x in the following situation:
In the above code, I used the watch window to edit the value of x from 5 to 10 prior to the Debug.Print statement.
...databox.text (from example code below) contains a large list of combined words(domain names) previously populated in the program. There is 1 per each line. In this example, it initially looks like:
thepeople.com
truehistory.com
workhorse.com
whatever.com
neverchange.com
...
The following code below saves the text inside databox to tlistfiltered.txt and then searches tlistfiltered.txt to retrieve all lines that contain any of the items in the list "arr()", and then populates listview(lv) with the results. This works just fine, but the results look like:
thepeople.com
truehistory.com
neverchange.com
...
but what I need is the "found string" (from arr()list to be Proper case so the result would be:
thePeople.com
trueHistory.com
neverChange.com
Here is the code....
Dim s As String = databox.Text
File.WriteAllText(dloc & "tlistfiltered.txt", s)
databox.Clear()
Dim text2() As String = System.IO.File.ReadAllLines(dloc & "tlistfiltered.txt")
Dim arr() As String = {"people", "history", "change"}
For index1 = 0 To arr.GetUpperBound(0)
Dim YesLines() As String = Array.FindAll(text2, Function(str As String)
Return str.Contains(arr(index1))
End Function).ToArray
databox.Visible = True
For index2 = 0 To YesLines.GetUpperBound(0)
Dim match As String = (YesLines(index2)) & vbCrLf
databox.AppendText(match)
Next
Next
s = databox.Text
File.WriteAllText(dloc & "tlistfilteredfinal.txt", s)
databox.Clear()
domains = (From line In File.ReadAllLines(dloc & "tlistfilteredfinal.txt") Select New ListViewItem(line.Split)).ToArray
lv.Items.Clear()
My.Computer.FileSystem.DeleteFile(dloc & "tlistfiltered.txt")
My.Computer.FileSystem.DeleteFile(dloc & "tlistfilteredfinal.txt")
BackgroundWorker1.RunWorkerAsync()
End Sub
Is there a way to do this on the fly? I have tried StrConv etc, but it will only convert the entire line to proper case. I only want the "found" word contained within the line to be converted....
edit:
after seeing #soohoonigan 's answer, i edited
databox.Visible = True
For index2 = 0 To YesLines.GetUpperBound(0)
Dim match As String = (YesLines(index2)) & vbCrLf
databox.AppendText(match)
Next
Next
to this:
databox.Visible = True
For index2 = 0 To YesLines.GetUpperBound(0)
Dim match As String = (YesLines(index2)) & vbCrLf
Dim myTI As System.Globalization.TextInfo = New System.Globalization.CultureInfo("en-US", False).TextInfo
If match.Contains(arr(index1)) Then
match = match.Replace(arr(index1), myTI.ToTitleCase(arr(index1)))
'StrConv(match, vbProperCase)
databox.AppendText(match)
End If
Next
and got the desired result!
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim test As String = "thepeople.com"
Dim search As String = "people"
Dim myTI As System.Globalization.TextInfo = New System.Globalization.CultureInfo("en-US", False).TextInfo
If test.Contains(search) Then
test = test.Replace(search, myTI.ToTitleCase(search))
MsgBox(test)
End If
Me.Close()
End Sub
End Class
I'm not sure to understand the need for using files for intermediate steps and deleting them at the end for example.
First step: getting the lines of the input
That can be done by using the Lines property of databox (which I suspect to be a TextBox or RichTextBox ; if it's not the case we can still use a Split on the Text property)
Dim lines = databox.Lines ' or databox.Text.Split({Environment.NewLine}, StringSplitOptions.RemoveEmptyEntries)
Second step: we want to filter those lines to keep only the ones containing the searched texts
For this there are several way, a simple one would be to use a Linq query to get the job done
Third step: transforming the result of the filter replacing the searched text by it's capitalized form
So we continue the started query and add a projection (or mapping) to do the transformation.
We need to use TextInfo.ToTitleCase for that.
' See soohoonigan answer if you need a different culture than the current one
Dim textInfo = System.Globalization.CultureInfo.CurrentCulture.TextInfo
Dim query = From word in arr
From line in lines
Where line.Contains(word)
Let transformed = line.Replace(word, textInfo.ToTitleCase(word))
select transformed
' We could omit the Let and do the Replace directly in the Select Clause
What I want to do is replace all 'A' in a string with "Bb". but it will only loop with the original string not on the new string.
for example:
AAA
BbAA
BbBbA
and it stops there because the original string only has a length of 3. it reads only up to the 3rd index and not the rest.
Dim txt As String
txt = output_text.Text
Dim a As String = a_equi.Text
Dim index As Integer = txt.Length - 1
Dim output As String = ""
For i = 0 To index
If (txt(i) = TextBox1.Text) Then
output = txt.Remove(i, 1).Insert(i, a)
txt = output
TextBox2.Text += txt + Environment.NewLine
End If
Next
End Sub
I think this leaves us looking for a String.ReplaceFirst function. Since there isn't one, we can just write that function. Then the code that calls it becomes much more readable because it's quickly apparent what it's doing (from the name of the function.)
Public Function ReplaceFirst(searched As String, target As String, replacement As String) As String
'This input validation is just for completeness.
'It's not strictly necessary.
'If the searched string is "null", throw an exception.
If (searched Is Nothing) Then Throw New ArgumentNullException("searched")
'If the target string is "null", throw an exception.
If (target Is Nothing) Then Throw New ArgumentNullException("target")
'If the searched string doesn't contain the target string at all
'then just return it - were done.
Dim foundIndex As Integer = searched.IndexOf(target)
If (foundIndex = -1) Then Return searched
'Build a new string that replaces the target with the replacement.
Return String.Concat(searched.Substring(0, foundIndex), replacement, _
searched.Substring(foundIndex + target.Length, searched.Length - (foundIndex + target.Length)))
End Function
Notice how when you read the code below, you don't even have to spend a moment trying to figure out what it's doing. It's readable. While the input string contains "A", replace the first "A" with "Bb".
Dim input as string = "AAA"
While input.IndexOf("A") > -1
input = input.ReplaceFirst(input,"A","Bb")
'If you need to capture individual values of "input" as it changes
'add them to a list.
End While
You could optimize or completely replace the function. What matters is that your code is readable, someone can tell what it's doing, and the ReplaceFirst function is testable.
Then, let's say you wanted another function that gave you all of the "versions" of your input string as the target string is replaced:
Public Function GetIterativeReplacements(searched As String, target As String, replacement As String) As List(of string)
Dim output As New List(Of String)
While searched.IndexOf(target) > -1
searched = ReplaceFirst(searched, target, replacement)
output.Add(searched)
End While
Return output
End Function
If you call
dim output as List(of string) = GetIterativeReplacments("AAAA","A","Bb")
It's going to return a list of strings containing
BbAAA, BbBbAA, BbBbBbA, BbBbBbBb
It's almost always good to keep methods short. If they start to get too long, just break them into smaller methods with clear names. That way you're not trying to read and follow and test one big, long function. That's difficult whether or not you're a new programmer. The trick isn't being able to create long, complex functions that we understand because we wrote them - it's creating small, simpler functions that anyone can understand.
Check your comments for a better solution, but for future reference you should use a while loop instead of a for loop if your condition will be changing and you're wanting to take that change into account.
I've made a simple example below to help you understand. If you tried the same with a for loop, you'd only get "one" "two" and "three" printed because the for loop doesn't 'see' that vals was changed
Dim vals As New List(Of String)
vals.Add("one")
vals.Add("two")
vals.Add("three")
Dim i As Integer = 0
While i < vals.Count
Console.WriteLine(vals(i))
If vals(i) = "two" Then
vals.Add("four")
vals.Add("five")
End If
i += 1
End While
If you do want to replace one by one instead of using the Replace function, you could use a while loop to look for the index of your search character/string, and then replace/insert at that index.
Sub Main()
Dim a As String = String.Empty
Dim b As String = String.Empty
Dim c As String = String.Empty
Dim d As Int32 = -1
Console.Write("Whole string: ")
a = Console.ReadLine()
Console.Write("Replace: ")
b = Console.ReadLine()
Console.Write("Replace with: ")
c = Console.ReadLine()
d = a.IndexOf(b)
While d > -1
a = a.Remove(d, b.Length)
a = a.Insert(d, c)
d = a.LastIndexOf(b)
End While
Console.WriteLine("Finished string: " & a)
Console.ReadLine()
End Sub
Output would look like this:
Whole string: This is A string for replAcing chArActers.
Replace: A
Replace with: Bb
Finished string: This is Bb string for replBbcing chBbrBbcters.
I was going to write a while loop to answer your question, but realized (with assistance from others) that you could just .replace(x,y)
Output.Text = Input.Text.Replace("A", "Bb")
'Input = N A T O
'Output = N Bb T O
Edit: There is probably a better alternative, but i quickly jotted this loop down, hope it helps.
You've said your new and don't fully understand while loops. So if you don't understand functions either or how to pass arguments to them, I'd suggest looking that up too.
This is your Event, It can be a Button click or Textbox text change.
'Cut & Paste into an Event (Change textboxes to whatever you have input/output)
Dim Input As String = textbox1.Text
Do While Input.Contains("A")
Input = ChangeString(Input, "A", "Bb")
' Do whatever you like with each return of ChangeString() here
Loop
textbox2.Text = Input
This is your Function, with 3 Arguments and a Return Value that can be called in your code
' Cut & Paste into Code somewhere (not inside another sub/Function)
Private Function ChangeString(Input As String, LookFor As Char, ReplaceWith As String)
Dim Output As String = Nothing
Dim cFlag As Boolean = False
For i As Integer = 0 To Input.Length - 1
Dim c As Char = Input(i)
If (c = LookFor) AndAlso (cFlag = False) Then
Output += ReplaceWith
cFlag = True
Else
Output += c
End If
Next
Console.WriteLine("Output: " & Output)
Return Output
End Function
I'm trying to filter a list based on input from a textbox. If the item doesn't contain the string, it is deleted from the list. Here is my subroutine:
Sub filterlists(filter As String)
Dim removalDifferential As Integer = 0
For colE As Integer = 0 To RadListView1.Items.Count
Try
Dim itemEpp As ListViewDataItem = Me.RadListView1.Items(colE)
Dim jobname As String = itemEpp(0)
If Not jobname.Contains(filter) Then
' MsgBox(jobname & " Contains " & filter)
RadListView1.Items.RemoveAt(colE - removalDifferential)
removalDifferential = removalDifferential + 1
End If
Catch
End Try
Next
End Sub
Currently this is not deleting the correct items. The TRY is there because when you delete an item the list index changes (which means the for loop length is wrong and will throw outofbounce errors). Any other loop options that will work here?
Assuming you really do want to delete any LVI which simply contains the filter text, you should loop backwards thru the items (any items, not just Listview items) so the index variable will in fact point to the next correct item after a deletion:
For n As Integer = RadListView1.Items.Count-1 to 0 Step -1
If radListView1.Items(n).Text.Contains(filter) Then
RadListView1.Items.RemoveAt(n)
End If
Next
Simple beginners issue here, go easy. I've got a few text boxes that the user can put values into + pick a date, and I want them to appear in a list box. Unfortunately only the 2nd text box's value appears multiple times. This can be seen here: http://i.stack.imgur.com/kCqrz.png
Here is the full form code: http://pastebin.com/MDb1hSCA
Here's where the data is added to an array:
stockArray(nofDataDay, lowValue) = possibleLow
stockArray(nofDataDay, highValue) = possibleHigh
stockArray(nofDataDay, openValue) = possibleOpen
stockArray(nofDataDay, closeValue) = possibleClose
dateArray(nofDataDay) = Convert.ToDateTime(WeatherDateTimePicker.Text)
nofDataDay = nofDataDay + 1
And here's where it's displayed:
For day = 0 To nofDataDay - 1
StockListBox.Items.Add(dateArray(day).ToShortDateString & _
delimiter & stockArray(day, openValue).ToString & _
delimiter & stockArray(day, closeValue).ToString & _
delimiter & stockArray(day, highValue).ToString & _
delimiter & stockArray(day, lowValue).ToString & _
delimiter & AverageStock(stockArray(day, lowValue), stockArray(day, highValue)))
Next
For some reason, it's only adding the Close value.
You never set the value of your column index variables (viz. openValue, closeValue, highValue, lowValue). They all default to zero, so you are in just adding the first column multiple times. You could set the value of them when you declare them, like this:
Dim lowValue As Integer = 0
Dim highValue As Integer = 1
Dim openValue As Integer = 2
Dim closeValue As Integer = 3
You'll need to declare your array larger too:
Dim stockArray(30, 3) As Integer
However, by default Dim declares fields as public, and since that's probably not what you really want, I would recommend changing them to private. Also, the column indexes really ought to be constants:
Private Const lowValue As Integer = 0
Private Const highValue As Integer = 1
Private Const openValue As Integer = 2
Private Const closeValue As Integer = 3
Private stockArray(30, 3) As Integer
However, this kind of bug would not be possible you designed your code better. Rather than using a two-dimensional array, I would recommend making a class that stores all the data for a single item. Then, rather than an array, use a List(T) object to store the list of items. For instance:
Public Class MyItem
Public Date As Date
Public LowValue As Integer
Public HighValue As Integer
Public OpenValue As Integer
Public CloseValue As Integer
End Class
Private myItems As New List(Of MyItem)()
Then, you can add the items like this:
Dim item As New MyItem()
item.Date = Convert.ToDateTime(WeatherDateTimePicker.Text)
item.LowValue = possibleLow
item.HighValue = possibleHigh
' ...
myItems.Add(item)
And then you can read the items from the list like this:
For Each item As MyItem in myItems
StockListBox.Items.Add(item.Date.ToShortDateString() & _
delimiter & item.OpenValue.ToString() & _
delimiter & item.CloseValue.ToString() & _
delimiter & item.HighValue.ToString() & _
delimiter & item.LowValue.ToString() & _
delimiter & AverageStock(item.LowValue, item.HighValue))
Next
As you can see, doing it that way is much more self-documenting, less confusing, and less bug-prone.