This is more like a logical question, I just need an idea on how to best approach this problem.
I am trying to do this in visual basic. I have to text box, in text box 1, I would have some text and if it contains certain word, I want to replace that with something else and have the new output in text box 2, after clicking on a convert button.
I know this can be done really easily with the replace function built in, but I am trying to do it without the replace function.
For example:
I want to replace "fox" with "dog"
Textbox 1: The quick brown fox jumped over the lazy dog.
Textbox 2: The quick brown dog jumped over the lazy dog.
I got it to work with the code below, but this only works for the first instance. How can I change my code for all instances.
String from InputText
Dim S1 As String
S1 = InputText.Text
'Position of start of "Edge Computer"
Dim pStart As Integer
pStart = S1.IndexOf("Edge Computer")
'Position of end of "Edge Computer"
Dim pEnd As Integer
pEnd = S1.IndexOf("r", pStart) + 1
'Actual old name as string
Dim strOld As String
strOld = S1.Substring(pStart, 13)
'New String for Output
Dim S2 As String
S2 = S1.Substring(0, pStart) & "3dg3" & S1.Substring(pEnd)
OutputText.Text = S2
Thanks
If you don't want to use replace you could use substring to select the text before and after the word that as to be replaced.
You did not post any code so it's hard to put an example that would fit you better
Dim NewText as String
If textbox1.text.IndexOf("OldWord") > - 1 Then
NewText = textbox1.text.Substring(0, textbox1.text.IndexOf("OldWord")) & "NewWord " & textbox1.text.Substring(textbox1.text.IndexOf("OldWord") + "Something".length, textbox1.text.length )
'Make sure you replacfe OldWold and NewWord to the specific text or variable
End If
To make it work with all instance of the word, you just need to replace the if by a loop
Dim NewText as String
Dim OldText as String = textbox1.text
While OldText.IndexOf("OldWord") > - 1
NewText = OldText.Substring(0, OldText.IndexOf("OldWord")) & "NewWord " & OldText.Substring(OldText.IndexOf("OldWord") + "OldWord".length, OldText.length )
OldText = OldText.Substring(OldText.IndexOf("OldWord") + "OldWord".length, OldText.length)
'Make sure you replace OldWold and NewWord to the specific text or variable
End While
Let me know if this works or not
Related
How can i check for a character after other text within a listbox?
e.g
Listbox contents:
Key1: V
Key2: F
Key3: S
Key4: H
How do I find what comes after Key1-4:?
Key1-4 will always be the same however what comes after that will be user defined.
I figured out how to save checkboxes as theres only 2 values to choose from, although user defined textboxes is what im struggling with. (I have searched for solutions but none seemed to work for me)
Usage:
Form1_Load
If ListBox1.Items.Contains("Key1: " & UsersKey) Then
TextBox1.Text = UsersKey
End If
Which textbox1.text would then contain V / whatever the user defined.
I did try something that kind of worked:
Form1_Load
Dim UsersKey as string = "V"
If ListBox1.Items.Contains("Key1: " & UsersKey) Then
TextBox1.Text = UsersKey
End If
but i'm not sure how to add additional letters / numbers to "V", then output that specific number/letter to the textbox. (I have special characters blocked)
Reasoning I need this is because I have created a custom save settings which saves on exit and loads with form1 as the built in save settings doesn't have much customization.
e.g Can't choose save path, when filename is changed a new user.config is generated along with old settings lost.
Look at regular expressions for this.
Using the keys from your sample:
Dim keys As String = "VFSH"
Dim exp As New RegEx("Key[1-4]: ([" & keys& "])")
For Each item As String in ListBox1.Items
Dim result = exp.Match(item)
If result.Success Then
TextBox1.Text = result.Groups(1).Value
End If
Next
It's not clear to me how your ListBoxes work. If you might find, for example, "Key 2:" inside ListBox1 that you need to ignore, you will want to change the [1-4] part of the expression to be more specific.
Additionally, if you're just trying to exclude unicode or punctuation, you could also go with ranges:
Dim keys As String = "A-Za-z0-9"
If you are supporting a broader set of characters, there are some you must be careful with: ], \, ^, and - can all have special meanings inside of a regular expression character class.
You have multiple keys, I assume you have multiple textboxes to display the results?
Then something like this would work. Loop thru the total number of keys, inside that you loop thru the alphabet. When you find a match, output to the correct textbox:
Dim UsersKey As String
For i As Integer = 1 To 4
For Each c In "ABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray()
UsersKey = c
If ListBox1.Items.Contains("Key" & i & ": " & UsersKey) Then
Select Case i
Case 1
TextBox1.Text = UsersKey
Case 2
TextBox2.Text = UsersKey
Case 3
TextBox3.Text = UsersKey
Case 4
TextBox4.Text = UsersKey
End Select
Exit For 'match found so exit inner loop
End If
Next
Next
Also, you say your settings are lost when the filename is changed. I assume when the version changes? The Settings has an upgrade method to read from a previous version. If you add an UpgradeSettings boolean option and set it to True and then do this at the start of your app, it will load the settings from a previous version:
If My.Settings.UpgradeSettings = True Then
My.Settings.Upgrade()
My.Settings.Reload()
My.Settings.UpgradeSettings = False
My.Settings.Save()
End If
Updated Answer:
Instead of using a listtbox, read the settings file line by line and output the results to the correct textbox based on the key...something like this:
Dim settingsFile As String = "C:\settings.txt"
If IO.File.Exists(settingsFile) Then
For Each line As String In IO.File.ReadLines(settingsFile)
Dim params() As String = Split(line, ":")
If params.Length = 2 Then
params(0) = params(0).Trim
params(1) = params(1).Trim
Select Case params(0)
Case "Key1"
Textbox1.Text = params(1)
Case "Key2"
Textbox2.Text = params(1)
End Select
End If
Next line
End If
You can associate text box with a key via its Name or Tag property. Lets say you use Name. In this case TextBox2 is associated with key2. TextBox[N] <-> Key[N]
Using this principle the code will look like this [considering that your list item is string]
Sub Test()
If ListBox1.SelectedIndex = -1 Then Return
Dim data[] As String = DirectCast(ListBox1.SelectedItem, string).Split(new char(){":"})
Dim key As String = data(0).Substring(3)
Dim val As String = data(1).Trim()
' you can use one of the known techniques to get control on which your texbox sits.
' I omit this step and assume "Surface1" being a control on which your text boxes sit
DirectCast(
(From ctrl In Surface1.Controls
Where ctrl.Name = "TextBox" & key
Select ctrl).First()), TextBox).Text = val
End Sub
As you can see, using principle I just explained, you have little parsing and what is important, there is no growing Select case if, lets say, you get 20 text boxes. You can add as many text boxes and as many corresponding list items as you wish, the code need not change.
I am writing a simple hangman program and I want to replace something in my variable which stores the letters of the word that have been found.
Here is the code:
Replace(wordLettersFound, Mid(wordLettersFound, counter, 1), letter)
wordLettersFound, counter and letter are 3 of the variables I am using.
The variable is all underscores before this script, but it does not change! Can anyone help me with this?
P.S.
I do not know what version of VB I am using, visual studio community 2015 just says 'visual basic'.
Replace doesn't modify the string but returns a new string with the replacement so you should assign it to the variable:
wordLettersFound = Replace(wordLettersFound, Mid(wordLettersFound, counter, 1), letter)
Another way to do replace,
Dim theLetters As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyzAAA"
theLetters = theLetters.Replace("A"c, "#"c)
There is another way to replace a character in a string. Using the Replace function is a bit awkward in your case because, at the start, all the characters are underscores - Replace as you're using it will replace all of them with the found character.
Instead, you can cut up the string to the piece to the left of the desired replacement, add in the replacement character, and add on the rest of the string. That line is the one after the comment "chop foundWord up and put the character in the right place" in this code:
Module Module1
Sub Main()
Dim wordToFind = "alphabet"
' make a string of dashes the same length as the word to find
Dim foundWord = New String("-"c, wordToFind.Length)
While foundWord <> wordToFind
Console.Write("Enter your guess for a letter: ")
Dim guess = Console.ReadLine()
' make sure the user has only entered one character
If guess.Length = 1 Then
' see if the letter is in the string
Dim pos = wordToFind.IndexOf(guess)
While pos >= 0
' chop foundWord up and put the character in the right place
foundWord = foundWord.Substring(0, pos) & guess & foundWord.Substring(pos + 1)
' see if there are any more of the same letter
pos = wordToFind.IndexOf(guess, pos + 1)
End While
' show the user the current progress
Console.WriteLine(foundWord)
Else
Console.WriteLine("Please enter just one letter!")
End If
End While
Console.WriteLine("You did it!")
Console.WriteLine("Press enter to leave the program.")
Console.ReadLine()
End Sub
End Module
N.B. Do not use all that code directly for homework because your teacher will find this. And that goes to anyone else doing homework - you know who you are ;)
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 am trying to take a string in a rich text box and replace them with a different string.
Now how this should work is that if two same characters are entered into the text box
e.g tt the "tt" will be replaced with "Ǿt" , it adds back one of the t's to the replaced string. Only the most recently entered string is manipulated if two same characters are entered .
I read the LAST string that is in the RichTextBox by using this method
Dim laststring As String = RichTextBox1.Text.Split(" ").Last
'hitting space bar breaks the operation so if i enter t t there will be no replacement
this is the replacement method which I use , it works correctly .
if laststring = "tt"
RichTextBox1 .Text = RichTextBox1 .Text.Replace("tt", "Ǿt")
This method is inefficient because i need to check id there are double letters for all letters and if i was to use this method it would tavke up a lot of code .
how can I accomplish this using a shorter method??
You need to put the if then section in a loop.
Dim holdstring As String
Dim doubleinstance() As String = {"bb", "tt", "uu"} ' array
Dim curstring As String = RichTextBox1.Text.Split(" ").Last
For Each item As String In doubleinstance
If RichTextBox1.Text.EndsWith(item) Then
holdstring = RichTextBox1.Text.Split(" ").Last.Length - 1 ' change to subtract 1 character from doubleinstance
RichTextBox1.Text = RichTextBox1.Text.Replace(curstring, "Ǿt" & holdstring)
MsgBox(curstring)
End If
Next item
Here's a bit of code to get you in the right direction...
There are a couple of variations of .Find, but you probably want to look at the .Select method.
With RichTextBox1
.Find("Don")
.SelectedText = "Mr. Awesome"
End With
Here is a way I came up with
Dim holdstring As String
Dim doubleinstance() As String = {"bb", "tt", "uu"} ' array
Dim curstring As String = RichTextBox1.Text.Split(" ").Last
If curstring = doubleinstance(0) And RichTextBox1.Text.EndsWith(doubleinstance(0)) Then
holdstring = RichTextBox1.Text.Split(" ").Last.Length - 1 ' change to subtract 1 character from doubleinstance
RichTextBox1.Text = RichTextBox1.Text.Replace(curstring, "Ǿt" + holdstring)
MsgBox(curstring)
End If
where i have doubleinstance(0) how do i get the if statement to not only check a single index but all of the index from 0 to 2 in this example ?
I'm making an application that will change position of two characters in Word.
Imports System.IO
Module Module1
Sub Main()
Dim str As String = File.ReadAllText("File.txt")
Dim str2 As String() = Split(str, " ")
For i As Integer = 0 To str2.Length - 1
Dim arr As Char() = CType(str2(i), Char())
For ia As Integer = 0 To arr.Length() - 1 Step 2
Dim pa As String
pa = arr(ia + 1)
arr(ia + 1) = arr(ia)
arr(ia) = pa
Next ia
For ib As Integer = 0 To arr.Length - 1
Console.Write(arr(ib))
File.WriteAllText("File2.txt", arr(ib))
Next ib
File.WriteAllText("File2.txt", " ")
Console.Write(" ")
Next i
Console.Read()
End Sub
End Module
For example:
Input: ab
Output: ba
Input: asdasd asdasd
Output: saadds saadds
Program works good, it is mixing characters good, but it doesn't write text to the file. It will write text in console, but not in file.
Note: Program is working only with words that are divisible by 2, but it's not a problem.
Also, it does not return any error message.
Your code is overwriting the file that you have already written with a single space (" ") each time round.
You should only open the file once, and append to it using a stream writer:
Using output = File.CreateText("file2.txt")
' Put the for loop here.
End Using
There are some other things wrong with your code. Firstly, use For Each instead of For, this makes your code much more simple and readable. Secondly, try to avoid For loops altogether where possible. For instance, instead of iterating over the characters to output them one at a time, just create a new string from the char array, and write that:
Dim shuffledWord As New String(arr)
output.Write(shuffledWord)
Some of your types are plain wrong, i.e. you are using String in places instead of Char. You should always use Option Strict On. Then the compiler will not tolerate such code.
You should also prefer to use framework methods over VB-specific methods. This makes it easier to understand for C# programmers, and also makes it easier to translate and change (that is, use the Split method of strings instead of a free function, use ToCharArray instead of a cast to Char() …).
Finally, use meaningful variable names. str, str2 and arr are particularly cryptic because they don’t tell the reader of the code anything of interest about the variables.
Sub Main()
Dim text As String = File.ReadAllText("File.txt")
Dim words As String() = str.Split(" "c)
Using output = File.CreateText("file2.txt")
For Each word In words
dim wordChars = word.ToCharArray()
For i As Integer = 0 To wordChars.Length - 1 Step 2
Dim tmp As Char = wordChars(i + 1)
wordChars(i + 1) = wordChars(i)
arr(i) = tmp
Next
Dim shuffledWord As New String(wordChars)
output.Write(shuffledWord + " ")
Console.Write(huffledWord + " ")
Next
End Using
Console.Read()
End Sub