I'm trying to find a way to trim strings before a substring, in a way that only the left of the string is returned.
Before:
[REMOVE] = 1 (Line0)
G77 H9002 (Line1)
[ZAXIS] = 25 (Line2)
After:
[REMOVE] = 1
G77 H9002
[ZAXIS] = 25
I want to trim the strings before the "(line" substring (removing all characters remaining on the right as well).
In VBA this was easily achievable but in VB .Net its not so straightforward.
Could you please direct me to a possible solution?
Thanks
Dim strs = File.ReadLines("c:\\SomeFile.txt") 'Read the file
Using sw = File.CreateText("c:\Target") 'File to save to
For Each str In strs
Dim i = str.LastIndexOf("(Line") 'Find the index to cut
Dim newStr = str.Substring(0, i) 'Cut the line at index
sw.WriteLine(newStr) 'Write new string to new file.
Next
End Using
Related
I have a String file with 8 items (separated by commas) in each row, e.g., CA,23456,aName,aType,anotherName,aWord,secondword,number. I want to create a new string of items consisting of the 2nd item (an Integer) of each row of the original file. I know there are many ways to do this but someone out there knows how to do it with very few lines of code, which is what I am looking for. I prefer not to use a parser.
The way to show what I have tried is to look at the code below.
Dim sn2 As String = ""
Dim sn2S As String = ""
Using readFile As New StreamReader(newFile1)
Do While readFile.Peek() <> -1
sn2S = readFile.ReadLine(1)
sn2 = sn2 & sn2S & ","
Loop
End Using
The code returns the second character of each row not the second item. What I hope to get is a string that looks like: 123,1345,4325,3321,3456,3211 etc. Where each number is the second item in each row of the original file.
You could split it up by cells
Dim row As String = "CA,23456,aName,aType,anotherName,aWord,secondword,number"
Dim cells() As String = row.Split(",")
Dim cellValue As String = cells(1)
But in your case, I would just do a search and Substring by the index of the delimiter.
Dim startPosition As Integer = row.IndexOf(",") + 1
Dim endPosition As Integer = row.IndexOf(",", startPosition)
Dim cellValue As String = row.Substring(startPosition, endPosition - startPosition)
If you have the whole file in memory, there could be some regex that could do the job with one pass.
As for this line
sn2 = sn2 & sn2S & ","
You might want to check at doing a join or using stringbuilder.
You could try
Dim sn2 As String = ""
Dim sn2S(7) As String = ""
Using readFile As New StreamReader(newFile1)
Do While readFile.Peek() <> -1
Array.Clear(sn25,0,sn25.Length)
sn2S = readFile.ReadLine(1).Split(",")
sn2 = sn2 & sn2S(1) & ","
Loop
End Using
In one line
Dim sn2 = String.Join(",", File.ReadAllLines(newFile1).Select(Function(s) s.Split(","c)(1)))
From the inside-out:
File.ReadAllLines(newFile1) splits the file into lines and results in a string array holding those lines, which is fed into...
...Select(Function(s) s.Split(","c)(1)) which operates on each line by splitting the line by comma s.Split(","c) and then indexing the resulting array (1) to return the second (zero-based) element. This is fed into...
String.Join(",", ... ) which takes those second elements and joins then together with comma.
I have an application that reads a 5gb text file line by line and converts double quoted strings that are comma delimited to pipe delimited format.
i.e. "Smith, John","Snow, John" --> Smith, John|Snow, John
I have provided my code below. My question is: Is there a more efficient way of processing large files?
Dim fName As String = "C:\LargeFile.csv"
Dim wrtFile As String = "C:\ProcessedFile.txt"
Dim strRead As New System.IO.StreamReader(fName)
Dim strWrite As New System.IO.StreamWriter(wrtFile)
Dim line As String = ""
Do While strRead.Peek <> -1
line = strRead.ReadLine
Dim pattern As String = "(,)(?=(?:[^""]|""[^""]*"")*$)"
Dim replacement As String = "|"
Dim regEx As New Regex(pattern)
Dim newLine As String = regEx.Replace(line, replacement)
newLine = newLine.Replace(Chr(34), "")
strWrite.WriteLine(newLine)
Loop
strWrite.Close()
UPDATED CODE
Dim fName As String = "C:\LargeFile.csv"
Dim wrtFile As String = "C:\ProcessedFile.txt"
Dim strRead As New System.IO.StreamReader(fName)
Dim strWrite As New System.IO.StreamWriter(wrtFile)
Dim line As String = ""
Do While strRead.Peek <> -1
line = strRead.ReadLine
line = line.Replace(Chr(34) + Chr(44) + Chr(34), "|")
line = line.Replace(Chr(34), "")
strWrite.WriteLine(line)
Loop
strWrite.Close()
I tested your code and attempted to make a speed improvement by accumulating output lines into a StringBuilder. I also moved the regex declaration outside the loop.
When that did not work, I examined the CPU usage and disk I/O with Windows Process Monitor and it turned out that the bottleneck is the CPU (even when using an HDD instead of an SSD).
That led me to try an alternative method for modifying the text: if all you need to do is replace "," with | and remove any remaining double-quotes, then
newLine = line.Replace(""",""", "|").Replace("""", "")
turns out to be much faster (roughly fourfold in my testing) than using a regex.
(Further improvement might be possible with multi-threading, as #Werdna suggested, as long as more than one processor is available and you can coordinate writing back the modified data in the correct order.)
Using streamreader to read line by line of a text file. When I get to a certain line (i.e., 123|abc|99999||ded||789), I want to replace ONLY the first empty area with text.
So far, I've been toying with
If sLine.Split("|")(3) = "" Then
'This is where I'm stuck, I want to replace that index with mmm
End If
I want the output to look like this: 123|abc|99999|mmm|ded||789
Considering you already have code determining if the "mmm" string needs to be added or not, you could use the following:
Dim index As Integer = sLine.IndexOf("||")
sLine = sLine.Insert(index + 1, "mmm")
You could split the string, modify the array and rejoin it to recreate the string:
Dim sLine = "123|abc|99999||ded||789"
Dim parts = sLine.Split("|")
If parts(3) = "" Then
parts(3) = "mmm"
sLine = String.Join("|", parts)
End If
I gather that if you find one or more empty elements, you want to replace the first empty element with data and leave the rest blank. You can accomplish this by splitting on the pipe to get an array of strings, iterate through the array and replace the first empty element you come across and exit the loop, and then rejoin your array.
Sub Main()
Dim data As String = "123||abc|99999||ded||789"
Dim parts = data.Split("|")
For index = 0 To parts.Length - 1
If String.IsNullOrEmpty(parts(index)) Then
parts(index) = "mmm"
Exit For
End If
Next
data = String.Join("|", parts)
Console.WriteLine(data)
End Sub
Results:
123|mmm|abc|99999||ded||789
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 am new to VB.Net 2008. I have a task to resolve, it is regading extracting characters from a long string to the console, the extracted text shall be reformatted and saved into a CSV file. The string comes out of a database.
It looks something like: UNH+RAM6957+ORDERS:D:96A:UN:EGC103'BGM+38G::ZEW+REQEST6957+9'DTM+Z05:0:805'DTM+137:20100930154
The values are seperated by '.
I can query the database and display the string on the console, but now I need to extract the
Keyword 'ORDERS' for example, and lets say it's following 5 Characters. So the output should look like: ORDERS:D:96A then I need to extract the keyword 'BGM' and its following five characters so the output should look like: BGM+38G:
After extracting all the keywords, the result should be comma seperated and look like:
ORDERS:D:96A,BGM+38G: it should be saved into a CSV file automatically.
I tried already:
'Lookup for containing KeyWords
Dim FoundPosition1 = p_EDI.Contains("ORDERS")
Console.WriteLine(FoundPosition1)
Which gives the starting position of the Keyword.
I tried to trim the whole thing around the keyword "DTM". The EDI variable holds the entire string from the Database:
Dim FoundPosition2 = EDI
FoundPosition2 = Trim(Mid(EDI, InStr(EDI, "DTM")))
Console.WriteLine(FoundPosition2)
Can someone help please?
Thank you in advance!
To illustrate the steps involved:
' Find the position where ORDERS is in the string.'
Dim foundPosition = EDI.IndexOf("ORDERS")
' Start at that position and extract ORDERS + 5 characters = 11 characters in total.'
Dim ordersData = EDI.SubString(foundPosition, 11)
' Find the position where BGM is in the string.'
Dim foundPosition2 = EDI.IndexOf("BGM")
' Start at that position and extract BGM + 5 characters = 8 characters in total.'
Dim bgmData = EDI.SubString(foundPosition2, 8)
' Construct the CVS data.'
Dim cvsData = ordersData & "," & bgmData
I don't have my IDE here, but something like this will work:
dim EDI as string = "UNH+RAM6957+ORDERS:D:96A:UN:EGC103'BGM+38G::ZEW+REQEST6957+9'DTM+Z05:0:805'DTM+137:20100930154"
dim result as string = KeywordPlus(EDI, "ORDER", 5) + "," _
+ KeywordPlus(EDI, "BGM", 5)
function KeywordPlus(s as string, keyword as string, length as integer) as string
dim index as integer = s.IndexOf(keyword)
if index = -1 then return ""
return s.substring(index, keyword.length + length)
end function
for the interrested people among us, I have put the code together, and created
a CSV file out of it. Maybe it can be helpful to others...
If EDI.Contains("LOC") Then
Dim foundPosition1 = EDI.IndexOf("LOC")
' Start at that position and extract ORDERS + 5 characters = 11 characters in total.'
Dim locData = EDI.Substring(foundPosition1, 11)
'Console.WriteLine(locData)
Dim FoundPosition2 = EDI.IndexOf("QTY")
Dim qtyData = EDI.Substring(FoundPosition2, 11)
'Console.WriteLine(qtyData)
' Construct the CSV data.
Dim csvData = locData & "," & qtyData
'Console.WriteLine(csvData)
' Creating the CSV File.
Dim csvFile As String = My.Application.Info.DirectoryPath & "\Test.csv"
Dim outFile As IO.StreamWriter = My.Computer.FileSystem.OpenTextFileWriter(csvFile, True)
outFile.WriteLine(csvData)
outFile.Close()
Console.WriteLine(My.Computer.FileSystem.ReadAllText(csvFile))
End IF
Have fun!