I have a text in database which is "computer-hardware". I used that code to split
' string seperated by colons '-'
Dim info As String = strcotegory
Dim arInfo As String() = New String(3) {}
' define which character is seperating fields
Dim splitter As Char() = {"-"c}
arInfo = info.Split(splitter)
For x As Integer = 0 To arInfo.Length - 1
Response.Write(arInfo(x) & "</br> ")
Next
but now I want to get "computer" in textbox1 and "hardware" in textbox2.
please guide me
If I understood you correctly, replace the For loop with the following lines of code:
textbox1.Text = arInfo(0)
textbox2.Text = arInfo(1)
By the way, initializing arInfo (... = New String(3) {}) is not necessary, since you overwrite the value of arInfo anyway (arInfo = ...).
Related
I have Textboxes Lines:
{ LstScan = 1,100, DrwR2 = 0000000043 }
{ LstScan = 2,200, DrwR2 = 0000000041 }
{ LstScan = 3,300, DrwR2 = 0000000037 }
I should display:
1,100
2,200
3,300
this is a code that I can't bring to a working stage.
Dim data As String = TextBox1.Lines(0)
' Part 1: get the index of a separator with IndexOf.
Dim separator As String = "{ LstScan ="
Dim separatorIndex = data.IndexOf(separator)
' Part 2: see if separator exists.
' ... Get the following part with Substring.
If separatorIndex >= 0 Then
Dim value As String = data.Substring(separatorIndex + separator.Length)
TextBox2.AppendText(vbCrLf & value)
End If
Display as follows:
1,100, DrwR2 = 0000000043 }
This should work:
Function ParseLine(input As String) As String
Const startKey As String = "LstScan = "
Const stopKey As String = ", "
Dim startIndex As String = input.IndexOf(startKey)
Dim length As String = input.IndexOf(stopKey) - startIndex
Return input.SubString(startIndex, length)
End Function
TextBox2.Text = String.Join(vbCrLf, TextBox1.Lines.Select(AddressOf ParseLine))
If I wanted, I could turn that entire thing into a single (messy) line... but this is more readable. If I'm not confident every line in the textbox will match that format, I can also insert a Where() just before the Select().
Your problem is you're using the version of substring that takes from the start index to the end of the string:
"hello world".Substring(3) 'take from 4th character to end of string
lo world
Use the version of substring that takes another number for the length to cut:
"hello world".Substring(3, 5) 'take 5 chars starting from 4th char
lo wo
If your string will vary in length that needs extracting you'll have to run another search (for example, searching for the first occurrence of , after the start character, and subtracting the start index from the newly found index)
Actually, I'd probably use Split for this, because it's clean and easy to read:
Dim data As String = TextBox1.Lines(0)
Dim arr = data.Split()
Dim thing = arr(3)
thing now contains 1,100, and you can use TrimEnd(","c) to remove the final comma
thing = thing.TrimEnd(","c)
You can reduce it to a one-liner:
TextBox1.Lines(0).Split()(3).TrimEnd(","c)
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 looking to parse this text file into strings to insert them into a database.
Source Text File gets read as the following string:
Line of unwanted text
Another line of unwanted data
Timestamp: 1/1/10 12:00 PM
ID: 1
Details: All data processed. Length will vary.
I'd like to just read Timestamp, ID and Details and place them into separate strings to insert them into a data table. What is the best method of capturing everything after the : and to the end of the line?
Dim Details as String = TextFile.Substring(Message.IndexOf("Details:"), X)
If you have to use a String as input, you can use String.Split to break it up into lines, and process each line. String.Substring can be used to extract the rest of the line - I've just hardcoded the starting positions below.
Dim timestamp As String = Nothing
Dim id As String = Nothing
Dim details As String = Nothing
For Each line In input.Split({vbCrLf, vbCr, vbLf}, StringSplitOptions.None)
If line.StartsWith("timestamp:", StringComparison.OrdinalIgnoreCase) Then
timestamp = line.Substring(10).Trim()
ElseIf line.StartsWith("id:", StringComparison.OrdinalIgnoreCase) Then
id = line.Substring(3).Trim()
ElseIf line.StartsWith("details:", StringComparison.OrdinalIgnoreCase) Then
details = line.Substring(8).Trim()
End If
Next
If you can change how you read the data, then the loop could just be:
For each line In File.ReadLines("your\file\name.txt")
...
Next
Assuming your files are flawless... One way to do it :
Imports System.IO
Dim AllLines() As String = File.ReadAllLines(FilePath)
Dim DatasIndex As Int32 = -1
For i As Int32 = 0 To AllLines.Length - 1
If AllLines(i).StartsWith("T") OrElse AllLines(i).StartsWith("t") Then
If AllLines(i).ToUpper().StartsWith("TIMESTAMP: ") Then
DatasIndex = i
Exit For
End If
End If
Next
If DatasIndex > -1 Then
' Dim ReadDate As Date = Date.Parse(AllLines(DatasIndex).Substring(11))
' Dim ReadID As Int32 = Integer.Parse(AllLines(DatasIndex + 1).Substring(4))
Dim ReadDate As String = AllLines(DatasIndex).Substring(11)
Dim ReadID As String = AllLines(DatasIndex + 1).Substring(4)
Dim ReadDetails As String = AllLines(DatasIndex + 2).Substring(9)
' send to database
End If
You didn't tell if Timestamp: , ID: and Details: Strings are always in the same order and has a trailing space after each property name.
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 have code below. How do I get strings inside brackets? Thank you.
Dim tmpStr() As String
Dim strSplit() As String
Dim strReal As String
Dim i As Integer
strWord = "hello (string1) there how (string2) are you?"
strSplit = Split(strWord, "(")
strReal = strSplit(LBound(strSplit))
For i = 1 To UBound(strSplit)
tmpStr = Split(strSplit(i), ")")
strReal = strReal & tmpStr(UBound(tmpStr))
Next
Dim src As String = "hello (string1) there how (string2) are you?"
Dim strs As New List(Of String)
Dim start As Integer = 0
Dim [end] As Integer = 0
While start < src.Length
start = src.IndexOf("("c, start)
If start <> -1 Then
[end] = src.IndexOf(")"c, start)
If [end] <> -1 Then
Dim subStr As String = src.Substring(start + 1, [end] - start - 1)
If Not subStr.StartsWith("(") Then strs.Add(src.Substring(start + 1, [end] - start - 1))
End If
Else
Exit While
End If
start += 1 ' Increment start to skip to next (
End While
This should do it.
Dim result = Regex.Matches(src, "\(([^()]*)\)").Cast(Of Match)().Select(Function(x) x.Groups(1))
Would also work.
This is what regular expressions are for. Learn them, love them:
' Imports System.Text.RegularExpressions
Dim matches = Regex.Matches(input, "\(([^)]*)\)").Cast(of Match)()
Dim result = matches.Select(Function (x) x.Groups(1))
Two lines of code instead of more than 10.
In the words of Stephan Lavavej: “Even intricate regular expressions are easier to understand and modify than equivalent code.”
Use String.IndexOf to get the position of the first opening bracket (x).
Use IndexOf again the get the position of the first closing bracket (y).
Use String.Substring to get the text based on the positions from x and y.
Remove beginning of string up to y+1.
Loop as required
That should get you going.
This may also work:
Dim myString As String = "Hello (FooBar) World"
Dim finalString As String = myString.Substring(myString.IndexOf("("), (myString.LastIndexOf(")") - myString.IndexOf("(")) + 1)
Also 2 lines.