I have a text, in this text I search for a file. I find it by searching for its extension but don't know the name of the file.
When I find this string, I have the index of the extension (indexof(".jpg"))
Now, I would need the full file name. The only thing I know is that the filename starts right after a ">" symbol, but there are many of these in the file. Is there a way for example to get the index of the ">" in a string, starting at a specific index, and going backwards?
Try this regular expression:
>([A-Za-z0-9-+. _]+[.]jpg)
or perhaps better:
>([^[\]\*\/\\<>|]+[.]jpg)
I'm probably missing an allowed character, but that covers most of it and should be easy enough to modify. Use the expression like this:
Public Iterator Function FindJPGFileNames(inpupText As String) As IEnumerable(Of String)
For Each match In RegEx.Matches(inputString, ">([^[\]\*\/\\<>|]+[.]jpg)")
Yield match.Groups(1).Value
Next match
End Function
or
Public Function FindJPGFileNames(inpupText As String) As IEnumerable(Of String)
Dim matches = RegEx.Matches(inputString, ">([^[\]\*\/\\<>|]+[.]jpg)")
Return matches.Select(Function(m) m.Groups(1).Value)
End Function
or in addition I also found this solution:
Private Function searchimages(ByVal s As String, ByVal ending As String) As List(Of String)
Dim los As New List(Of String)
Dim position As Integer = 0
While position <> -1
position = s.IndexOf(ending, position, StringComparison.CurrentCultureIgnoreCase)
If position <> -1 Then
Dim endPosition As Integer = position + ending.Length
Dim startposition As Integer = s.LastIndexOf(">", position - 1, StringComparison.CurrentCultureIgnoreCase) + 1
los.Add(s.Substring(startposition, endPosition - startposition))
position = endPosition
End If
End While
Return (los)
End Function
Related
I would like to ask for your help regarding my problem. I want to create a module for my program where it would read .txt file, find a specific value and insert it to the text box.
As an example I have a text file called system.txt which contains single line text. The text is something like this:
[Name=John][Last Name=xxx_xxx][Address=xxxx][Age=22][Phone Number=8454845]
What i want to do is to get only the last name value "xxx_xxx" which every time can be different and insert it to my form's text box
Im totally new in programming, was looking for the other examples but couldnt find anything what would fit exactly to my situation.
Here is what i could write so far but i dont have any idea if there is any logic in my code:
Dim field As New List(Of String)
Private Sub readcrnFile()
For Each line In File.ReadAllLines(C:\test\test_1\db\update\network\system.txt)
For i = 1 To 3
If line.Contains("Last Name=" & i) Then
field.Add(line.Substring(line.IndexOf("=") + 2))
End If
Next
Next
End Sub
Im
You can get this down to a function with a single line of code:
Private Function readcrnFile(fileName As String) As IEnumerable(Of String)
Return File.ReadLines(fileName).Where(Function(line) RegEx.IsMatch(line, "[[[]Last Name=(?<LastName>[^]]+)]").Select(Function(line) RegEx.Match(line, exp).Groups("LastName").Value)
End Function
But for readability/maintainability and to avoid repeating the expression evaluation on each line I'd spread it out a bit:
Private Function readcrnFile(fileName As String) As IEnumerable(Of String)
Dim exp As New RegEx("[[[]Last Name=(?<LastName>[^]]+)]")
Return File.ReadLines(fileName).
Select(Function(line) exp.Match(line)).
Where(Function(m) m.Success).
Select(Function(m) m.Groups("LastName").Value)
End Function
See a simple example of the expression here:
https://dotnetfiddle.net/gJf3su
Dim strval As String = " [Name=John][Last Name=xxx_xxx][Address=xxxx][Age=22][Phone Number=8454845]"
Dim strline() As String = strval.Split(New String() {"[", "]"}, StringSplitOptions.RemoveEmptyEntries) _
.Where(Function(s) Not String.IsNullOrWhiteSpace(s)) _
.ToArray()
Dim lastnameArray() = strline(1).Split("=")
Dim lastname = lastnameArray(1).ToString()
Using your sample data...
I read the file and trim off the first and last bracket symbol. The small c following the the 2 strings tell the compiler that this is a Char. The braces enclosed an array of Char which is what the Trim method expects.
Next we split the file text into an array of strings with the .Split method. We need to use the overload that accepts a String. Although the docs show Split(String, StringSplitOptions), I could only get it to work with a string array with a single element. Split(String(), StringSplitOptions)
Then I looped through the string array called splits, checking for and element that starts with "Last Name=". As soon as we find it we return a substring that starts at position 10 (starts at zero).
If no match is found, an empty string is returned.
Private Function readcrnFile() As String
Dim LineInput = File.ReadAllText("system.txt").Trim({"["c, "]"c})
Dim splits = LineInput.Split({"]["}, StringSplitOptions.None)
For Each s In splits
If s.StartsWith("Last Name=") Then
Return s.Substring(10)
End If
Next
Return ""
End Function
Usage...
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
TextBox1.Text = readcrnFile()
End Sub
You can easily split that line in an array of strings using as separators the [ and ] brackets and removing any empty string from the result.
Dim input As String = "[Name=John][Last Name=xxx_xxx][Address=xxxx][Age=22][Phone Number=8454845]"
Dim parts = input.Split(New Char() {"["c, "]"c}, StringSplitOptions.RemoveEmptyEntries)
At this point you have an array of strings and you can loop over it to find the entry that starts with the last name key, when you find it you can split at the = character and get the second element of the array
For Each p As String In parts
If p.StartsWith("Last Name") Then
Dim data = p.Split("="c)
field.Add(data(1))
Exit For
End If
Next
Of course, if you are sure that the second entry in each line is the Last Name entry then you can remove the loop and go directly for the entry
Dim data = parts(1).Split("="c)
A more sophisticated way to remove the for each loop with a single line is using some of the IEnumerable extensions available in the Linq namespace.
So, for example, the loop above could be replaced with
field.Add((parts.FirstOrDefault(Function(x) x.StartsWith("Last Name"))).Split("="c)(1))
As you can see, it is a lot more obscure and probably not a good way to do it anyway because there is no check on the eventuality that if the Last Name key is missing in the input string
You should first know the difference between ReadAllLines() and ReadLines().
Then, here's an example using only two simple string manipulation functions, String.IndexOf() and String.Substring():
Sub Main(args As String())
Dim entryMarker As String = "[Last Name="
Dim closingMarker As String = "]"
Dim FileName As String = "C:\test\test_1\db\update\network\system.txt"
Dim value As String = readcrnFile(entryMarker, closingMarker, FileName)
If Not IsNothing(value) Then
Console.WriteLine("value = " & value)
Else
Console.WriteLine("Entry not found")
End If
Console.Write("Press Enter to Quit...")
Console.ReadKey()
End Sub
Private Function readcrnFile(ByVal entry As String, ByVal closingMarker As String, ByVal fileName As String) As String
Dim entryIndex As Integer
Dim closingIndex As Integer
For Each line In File.ReadLines(fileName)
entryIndex = line.IndexOf(entry) ' see if the marker is in our line
If entryIndex <> -1 Then
closingIndex = line.IndexOf(closingMarker, entryIndex + entry.Length) ' find first "]" AFTER our entry marker
If closingIndex <> -1 Then
' calculate the starting position and length of the value after the entry marker
Dim startAt As Integer = entryIndex + entry.Length
Dim length As Integer = closingIndex - startAt
Return line.Substring(startAt, length)
End If
End If
Next
Return Nothing
End Function
I have looked on the web and I cannot find anything that helps me, all I can find is changing the characters into ASCII or Hexadecimal. However I would like to do it a different way. For example, say the string that got passed in was abcdef, I would like to have a key which changes these characters into another string such as qwpolz. Is there an easier way than declaring each character in the alphabet to be another character like:
Dim sText As String = "Hello"
Dim sEncode As String = ""
Dim iLength As Integer
Dim i As Integer
iLength = Len(sText)
For i = 1 To iLength
sEncode = sEncode ????
Next
Return sEncode
And then have a very lengthy loop which checks for these loops? There must be a much simpler way. Can anybody help by pointing me in the right direction?
Edit: Why downvote? Seriously, it's a legitimate question. Instead of downvoting for no reason, just move onto another question.
Well actually, this sounds like a Caesar sipher
Private Overloads Shared Function Encrypt(ByVal ch As Char, ByVal code As Integer) As Char
If Not Char.IsLetter(ch) Then
Return ch
End If
Dim offset As Char = IIf(Char.IsUpper(ch), "A", "a")
Return CType((((ch + (code - offset)) Mod 26) + offset),Char)
End Function
Private Overloads Shared Function Encrypt(ByVal input As String, ByVal code As Integer) As String
Return New String(input.ToCharArray.Select(() => { }, Encrypt(ch, code)).ToArray)
End Function
Private Shared Function Decrypt(ByVal input As String, ByVal code As Integer) As String
Return Encrypt(input, (26 - code))
End Function
Note that this assumes, that you use English alphabet. In general case where for example you have 'ä', 'ö', 'š', 'ž', 'ß', 'õ', 'ü' etc. this would not work. In that case it is simpler to just create a list/dictionary of your ordered alphabet and use it.
Example use:
encrypted = Encrypt(sText, 5)
decypted = Decrypt(encrypted, 5)
Sounds as if you want to modify a string by replacing each character with a different character according to a mapping table. An efficient approach is to use a Dictionary(Of Char, Char). But easier to write and maintain is something like this:
Shared ReadOnly replaceChars As String = "abcdef"
Shared ReadOnly withChars As String = "qwpolz"
Public Shared Function ReplaceAll(input As String) As String
Dim newChars = From c In input
Let index = replaceChars.IndexOf(c)
Select If(index >= 0, withChars(index), c)
Return String.Concat(newChars)
End Function
So the first string contains the chars that you want to replace and the second the replacement characters. Both strings must have the same length.
If you want to support case insensitivity:
Public Shared Function ReplaceAll(input As String, comparison As StringComparison) As String
Dim newChars = From c In input
Let index = replaceChars.IndexOf(c.ToString(), comparison)
Select If(index >= 0, withChars(index), c)
Return String.Concat(newChars)
End Function
Note that this is also a loop. There is no way to avoid some kind of loops if you want to replace multiple characters or strings.
I have string say "c:\debug\ *.txt"
In Debug folder there are severeal .txt files , say test1.txt test2.txt test3.txt .
How can I get from this string c:\debug\ *.txt an array of wildcard files?
a(0)=c:\debug\test1.txt
a(1)=c:\debug\test2.txt
a(2)=c:\debug\test3.txt
It is also possible that the string would be something like "C:\logs\12*\ *.log"
a(0)=C:\logs\120114\01.log
a(0)=C:\logs\120114\02.log
a(0)=C:\logs\120114\03.log
etc.
Anyone have any ideas on this?
I use the following code:
Dim Path As String = "C:\debug"
Dim Dir As New DirectoryInfo(Path)
Dim q = (From x In Dir.GetFiles("*.txt", SearchOption.AllDirectories) Select x.FullName).ToArray
You might need to
Import System.IO
Import System.Linq
Basically your key for the requirement is SearchOption.AllDirectories which iterates through sub directories as well.
This should do it for you. It'll handle wildcards in directory part and filename part
Private Function GetFiles(ByVal Path As String) As List(Of String)
Dim drivePart As String, dirPart As String, filePart As String
drivePart = Path.Substring(0, Path.IndexOf("\") + 1)
dirPart = Path.Substring(Path.IndexOf("\") + 1, Path.LastIndexOf("\") - Path.IndexOf("\") - 1)
filePart = Path.Substring(Path.LastIndexOf("\") + 1)
Dim directories As New List(Of String)
Dim files As New List(Of String)
'' Walk directory tree finding matches
'' This should handle wildcards in any part of the path
Dim currentIndex As Integer = 0
Dim directoryMatch As String() = dirPart.Split("\")
For Each directory As String In directoryMatch
WalkDirectories(drivePart, directories, directoryMatch, currentIndex)
currentIndex += 1
Next
For Each directory As String In directories
files.AddRange(System.IO.Directory.GetFiles(directory, filePart))
Next
Return files
End Function
Private Sub WalkDirectories(ByVal dirPart As String, ByVal directories As List(Of String), ByVal directoryMatch As String(), ByVal currentIndex As Integer)
If currentIndex = directoryMatch.Length Then Return
For Each d As String In System.IO.Directory.GetDirectories(dirPart, directoryMatch(currentIndex))
directories.Add(d)
WalkDirectories(System.IO.Path.Combine(dirPart, d), directories, directoryMatch, currentIndex + 1)
Next
End Sub
Edit: just noticed that it wont handle UNC paths but it should be pretty easy to modify for that if you need to
Editted again to handle multiple directory levels and wildcards at multiple levels (eg C:\debug\12*\log1*\errors*.txt
Use the GetFiles from My.Computer.System and the ReadOnlyCollection(of String) from the system.collections.objectModel import and a searchoption as desired (top or all)
sPath = "C:\debug" ' your desired path
sFile1 = "t*.txt" ' your desired search pattern with * wildcard
sFile2 = "test?.txt" ' your desired search pattern with ? wildcard
dim lstFiles as system.collections.ObjectModel.ReadOnlyCollection(of String) = My.Computer.Filesystem.GetFiles(sPath, FileIO.SearchOption.SearchTopLevelOnly, sFile1)
'lstfiles contains all the files that match your selection
'if you really need an array you can convert the list to array here
dim i as integer = 0
for each sFile as string in lstfiles
a(i)=sfile
i+=1
next
You could use the 'Like' keyword:
' For your example, call this function with root = "C:\logs" and wild = "12*\*.log"
Friend Function GetMyFiles(root As String, wild As String, Optional allowsub As Boolean = True) As List(Of String)
Dim a As New List(Of String), pattern As String
' ensure root ends with a \
If Not root.EndsWith("\") Then root &= "\"
' the extra * allows for subdirectories in between, if required
pattern = root & If(allowsub, "*", "") & wild
For Each f As String In My.Computer.FileSystem.GetFiles(root, FileIO.SearchOption.SearchAllSubDirectories)
If f Like pattern Then a.Add(f)
Next
Return a
End Function
Of course, if you hit a protected system directory, it'll fail.
This function is just to demonstrate the 'Like' keyword.
It will work if 'root' isn't a drive root (e.g. C:).
Done properly, a separate function would collect directories first, each tested for access permissions in a Try/Catch block. Here's how that looks:
Friend Function GetAllAccessibleDirs(ByRef Dir As String, Optional inclDir As Boolean = True, Optional Sort As Boolean = False) As List(Of String)
Dim D As New List(Of String), Q As New Queue(Of String), dummy As DirectoryInfo, s As String
If inclDir Then D.Add(Dir)
Q.Enqueue(Dir)
While Q.Count
For Each s In GetTopLevelDirs(Q.Dequeue)
Try
dummy = My.Computer.FileSystem.GetDirectoryInfo(s)
D.Add(s)
Q.Enqueue(s)
Catch
' Inaccessible folder
End Try
Next
End While
If Sort AndAlso D.Count Then D.Sort()
Return D
End Function
Friend Function GetTopLevelDirs(ByRef dir As String) As List(Of String)
Try
Return My.Computer.FileSystem.GetDirectories(dir, FileIO.SearchOption.SearchTopLevelOnly).ToList
Catch
Return New List(Of String)
End Try
End Function
I'm trying to count the number of an item in a text file, by counting each instance the item was entered into the file earlier on in the program.
I already have the text read from the file and in a text box. The problem is that my current code was just counting the characters in the textbox and not the number of times my desired word was in the file.
For Each desiredword As String In txtContentofFile.Text
intdesiredword = intdesiredword + 1
txtdesiredwordcount.Text = intdesiredword
Next
This counts the characters in the textbox instead of counting the number of desired words. I tried repeatedly before asking help and searched extensively, but I just don't understand what's wrong with my code. Please help :)
You can use Split Function :
C#:
int count = txtContentofFile.Text.Split(desiredword).Length - 1;
VB.net:
Dim count As Integer = txtContentofFile.Text.Split(desiredword).Length - 1
I prefer to use Regular Expressions in this type of situation. They are very tricky to understand but they are extremely powerful and typically faster than other string manipulation techniques.
Dim AllMatchResults As MatchCollection
Try
Dim RegexObj As New Regex(desiredword)
AllMatchResults = RegexObj.Matches(txtContentofFile.Text)
If AllMatchResults.Count > 0 Then
' Access individual matches using AllMatchResults.Item[]
Else
' Match attempt failed
End If
Catch ex As ArgumentException
'Syntax error in the regular expression
End Try
In your case you are looking for the value from AllMatchResults.Count.
Using a great Regular Expression tool like RegexBuddy to build and test the expressions is a great help too. (The above code snippet was generated by RegexBuddy!)
Try this:
Dim text As String = IO.File.ReadAllText("C:\file.txt")
Dim wordsToSearch() As String = New String() {"Hello", "World", "foo"}
Dim words As New List(Of String)()
Dim findings As Dictionary(Of String, List(Of Integer))
'Dividing into words
words.AddRange(text.Split(New String() {" ", Environment.NewLine()}, StringSplitOptions.RemoveEmptyEntries))
findings = SearchWords(words, wordsToSearch)
Console.WriteLine("Number of 'foo': " & findings("foo").Count)
Function used:
Private Function SearchWords(ByVal allWords As List(Of String), ByVal wordsToSearch() As String) As Dictionary(Of String, List(Of Integer))
Dim dResult As New Dictionary(Of String, List(Of Integer))()
Dim i As Integer = 0
For Each s As String In wordsToSearch
dResult.Add(s, New List(Of Integer))
While i >= 0 AndAlso i < allWords.Count
i = allWords.IndexOf(s, i)
If i >= 0 Then dResult(s).Add(i)
i += 1
End While
Next
Return dResult
End Function
You will have not only the number of occurances, but the index positions in the file, grouped easily in a Dictionary.
Try the following code
Function word_frequency(word_ As String, input As String) As Integer
Dim ct = 0
Try
Dim wLEN = word_.Length
Do While input.IndexOf(word_) <> -1
Dim idx = input.IndexOf(word_) + wLEN
ct += 1
input = input.Substring(idx)
Loop
Catch ex As Exception
End Try
Return ct
End Function
How do I count a specific word in a specific text file ussing vb.net
Something like this would help you:
Private Function GetWordCountInFile(ByVal filepath As String, ByVal word As String)
Dim dict As New Dictionary(Of String, Integer)()
Dim lst As New List(Of String)(IO.File.ReadAllText(filepath).Split(" "))
For Each entry As String In lst
If Not (dict.ContainsKey(entry.ToLower.Trim)) Then
dict.Add(entry.ToLower.Trim, 1)
Else
dict(entry.ToLower.Trim) += 1
End If
Next
lst.Clear()
Return dict(word.ToLower.Trim)
End Function
you can use it like this:
Dim count As Integer = GetWordCountInFile("../../Sample.txt", "sample")
This will look for a word "sample" in a text file "sample.txt" and returns a count.
Also, may not a good one but a single line approach would be:
Private Function GetWordCountInFile(ByVal filepath As String, ByVal word As String)
Return System.Text.RegularExpressions.Regex.Matches(IO.File.ReadAllText(filepath), "(?i)\b(\s+)?" & word & "(\s+|\S{0})\b|^" & word & "\.?$|" & word & "[\.\,\;]").Count
End Function
OR something like this: (no need to declare additional variable to hold word count)
Private Function GetWordCountInFile(ByVal filepath As String, ByVal word As String)
Dim lst As New List(Of String)(IO.File.ReadAllText(filepath).ToLower.Split(New Char() {" ", ",", ";", ".", ":"}))
Return lst.FindAll(Function(c) c.Trim() = word.ToLower).Count()
End Function
Assuming 4.0...
The word must be an exact match (excluding mixed case). If you want to count matching sub-words, such as searching for "sub" and counting "subway" as a word, change to LCase(strWord).Contains(LCase("TargetWord"))...
Dim intCount As Integer = 0
IO.File.ReadAllText("C:\file.txt").Split(" ").ToList().ForEach(Sub(strWord As String)
If LCase(strWord) = LCase("TargetWord") Then
intCount += 1
End If
End Sub)
MsgBox(CStr(intCount))