I'm trying to parse a long boring text document and parse and format it.
"7/29/2012 1:25:20 PM","Summary Plan/Second Floor /Master_VAV_2-24","Source :OEnd"
"7/29/2012 11:25:23 AM","Summary Plan/Second Floor /Master_VAV_2-24","Source :OStart"
I'd like to parse each value between the quotes but I cant find anything online to help me, I believe it's a matter of knowing what to call it and search for.
"date", "location", "type" would be the 3 values I want to parse it into, then I could run a loop for each item in datatable and format it as required.
ANY HELP would be great, thank you!
I'm thinking of using RegEx to get the rows and add them manually to an array, something like this.
Dim rx As New Regex(",", RegexOptions.IgnoreCase Or RegexOptions.Multiline)
Dim matches As MatchCollection = rx.Matches(strSource)
For Each match As Match In matches
Dim matchValue As String = match.Value
If Not list.Contains(matchValue) Then
list.Add(matchValue)
End If
Next
This format appears to be CSV - use one of the many free and open source CSV parsers (google ".NET CSV parser" will return many results.
There is one that comes built in, in the Microsoft.VisualBasic.FileIO namespece - the TextFieldParser.
Related
My question is: I have a program that fetches the whole source code of a specified URL. The source code will be saved in a variable.
Part of the source code looks like this:
"thumbnail_src":"https:\/\/scontent-fra3-1.blablabla.com\/t51.2885-15\/s640x640\/sh0.08\/e35\/1234567_984778981596410_1107218704_n.jpg","is_video":false,
The code is has quite a bunch of those URLs. I want my code to look for the part "thumbnail_src":" as a marker for beginning the extraction process and stop the extraction at ","is_video":
This should be obviously done in a loop until all URLs are being extracted and saved into a listing variable.
How can I achieve that?
I am trying to get that Regexp into my sourcecode. The one that codexer wrote, which is correct but I am getting eerrors in visual basic net.
Dim regex As Regex = New Regex("thumbnail_src""": """(.*)""","""is_video")
Dim match As Match = regex.Match(sourceString)
If match.Success Then
Console.WriteLine(match.Value)
End If
I tried it this way..and also that way:
Dim regex As Regex = New Regex("thumbnail_src":"(.*)","is_video")
Something is wrong the way I am entering the regex code.
Here is the correct one I need to implement:
https://regex101.com/r/hK0xH8/4
thumbnail_src":"(.*)","is_video
In light of your recent edit I am going to redo this answer.
Since it looks like everything is coming in on one line of text here is how I would handle it.
Dim LargetxtLine as String = TheVeryLargylineofText
Dim CommaSplit as String() = LargetxtLine.split(","c)
Dim URLList as New List(of String)
Dim RG as New Regex("\"":\""(.*)\""")
For Each str as String in CommaSplit
If str.contains("thumbnail_src") Then
URLList.Add(RG.Match(str).value)
End If
Next
This will break up the long line of text into managable chunks and then it uses regex to add it to a list of URL's (URLList)
From there you can do just about anything with a list(of String).
There is another way of doing it without splitting on the ,'s
if you use this Regex
"thumbnail_src\"":\""(.*?)\"",\""is_video"
Adding the "?" in there turns it into a greedy statement meaning that it will stop at the first occurance.
After that you could create a URLList like this
DIM RG as New Regex("thumbnail_src\"":\""(.*?)\"",\""is_video")
Dim URLList as MatchCollection = RG.Matches(reallybigString)
It's really personal preference
I've been asked at work to create a project to open a CSV and then use a set of conditions to change and save the data using Visual Basic.net (2010)
Although I am comfortable creating files in vb and opening them again into vb, I don't know how to declare the fields so I can query them. For example:
if field1 = "Yes" and field2 = "Blue" then textbox1.text = "abcd"
Then at a later stage I want to export a file which I'm happy doing where it writes lines to create a new CSV which could be Field1, textbox1.text, Field3 and so on
Also, would I have to declare line1.field1 and line2.field1 or could I declare line2.field1 as field25 for example or whatever the next sequential number may be?
Thanks
How are you going to read from the file?
If you do File.ReadAllLines
what does it return? A string array.
Does a string array have properties like line1? No, but they do have indexers.
How do you access an element in a string array? With a indexer,
e.g. array(0).
Does an string have properties like field1? Nope.
Can you use String.Split to split on the commas and separate the fields? Yes.
Could you write a class that has specific properties defined for each field that has a constructor that'd take a string that represents a row and put the value into the correct fields? Yes.
Could the same class know how to convert itself into a single CSV style line? Yup.
Are there other library that could help you do this? Probably.
All that being said, you can probably get away with doing something simple like this (warning: naive code sample):
Dim fileName = "C:\testFile.csv"
Dim lines = File.ReadAllLines(fileName)
Dim output As New List(Of String)
For Each line In lines
Dim fields = line.Split(","c)
fields(0) = "000" 'Blank out number
If fields(3) = "Y" Then 'Change Y to True
fields(3) = "True"
End If
output.Add(String.Join(","c, fields))
Next
File.WriteAllLines(fileName, output)
I gave it input that looked like this:
123,abc,Y,Y,N
456,def,Y,N,Y
789,ghi,N,Y,Y
012,jkl,N,N,N
and it changed the file to this:
000,abc,Y,True,N
000,def,Y,N,Y
000,ghi,N,True,Y
000,jkl,N,N,N
Utilities for working with CSV will do a better job than this. There are various ways this won't work (doesn't handle any escape sequences, etc.) but this could be sufficient if you're just wanting to do something quick and dirty and don't need to worry about some things. At the very least hopefully it'll give you a better understanding of how you'd go about solving a problem like this.
I'd recommend writing the output to a different file to test.
I am writing a program in Visual Basic that writes and reads to and from a Microsoft Access Database. When reading from the database, one of the functions that I am trying to perform is to determine the number of lines in a multi-line string that was written to the database and then subsequently read from the database. Here's what I have tried so far with no luck.
Dim stringLines() As String = databaseReader("multilineString").ToString.Split(CChar("Environment.NewLine"))
Dim stringLinesCount As Integer = stringLines.Length
For some reason, this always results in stringLinesCount being equal to one, regardless of how many lines the string has. In this example, I am using Environment.NewLine, but I have tried \n, \r, vbCr, vbLf, and vbCrLf as well, and they all result in a value of one. Since none of these seem to be working, what can I use instead to determine the number of lines?
Edit:
Dim splitCharacters() As Char = {CChar(vbCrLf), CChar(vbCr), CChar(vbLf), CChar(Environment.NewLine), CChar("\n"), CChar("\r")}
Dim stringLines() As String = databaseReader("multilineString").ToString.Split(splitCharacters)
Dim stringLinesCount As Integer = stringLines.Length
Since Chris Dunaway provided the answer that I view as helpful but posted it as a comment, here's what he said:
VB cannot use C# style escape sequences, so CChar("\n") and CChar("\r") is meaningless in VB. Also, calling CChar("Environment.NewLine") is wrong because you are trying to convert the actual string "Environment.NewLine" to a single character, which obviously won't work. You can just use Environment.Newline directly in the call to String.Split.
If Chris decides to post his comment as an answer, please let me know so that I may remove this.
im trying to extract a quote from this quote gen URL 'http://www.quotedb.com/quote/quote.php?action=random_quote'. i need it to extract JUST the quote and optionally the person who made the quote. this is an example reply from the generator.
document.write('When nothing seems to help, I go and look at a stonecutter hammering away at his rock perhaps a hundred times without as much as a crack showing in it. Yet at the hundred and first blow it will split in two, and I know it was not that blow that did it, but all that had gone before.');
document.write('More quotes from Jacob August Riis');
I know i need to parse it to extract the quote itself but im not to sure how to so this.
I know how to download the string of the quote but not how to extract it. So this is all i have currently:
Dim Cient As New System.Net.WebClient
Dim grab = Cient.DownloadString("http://www.quotedb.com/quote/quote.php?action=random_quote")
any help is greatly appreciated!
Someone else could probably come up with more elegant regular expressions, but this should work. Just a couple of regular expressions to extract the parts of the returned data that you are interested in.
Dim quote = RegEx.Matches(grab, "document\.write\('(.*?)<br>'\);")(0).Groups(1).Value
Dim author = RegEx.Matches(grab, "document\.write\('<i>.*?>(.*?)</a></i>'\);")(0).Groups(1).Value
I'm not a fan of parsing HTML with Regex, but since all of these come back with the same grammar so to speak, we can consider it regular for this case.
Dim pattern As String = <![CDATA[document\.write\('(?<quote>.*)<br\>'\);\ndocument\.write\('.*href=\"(?<url>[^\"]*)\">(?<author>[^<]*)</a>.*'\).*]]>.Value
Dim quoteRegex As New Regex(pattern, RegexOptions.Compiled Or RegexOptions.IgnoreCase Or RegexOptions.Singleline)
Dim Cient As New System.Net.WebClient
Dim grab = Cient.DownloadString("http://www.quotedb.com/quote/quote.php?action=random_quote")
Dim matches As MatchCollection = quoteRegex.Matches(grab)
For Each m As Match In matches
Console.WriteLine("Quote: {0}", m.Groups("quote"))
Console.WriteLine("Author: {0}", m.Groups("author"))
Console.WriteLine("URL: {0}", m.Groups("url"))
Next
This finds the quote (text within the first document.write() ignoring the quotes and the <br> tag), the Author of the quote (the Textual display of the anchor tag) and then the URL for more quotes (the href attribute of the anchor)
I declared the pattern by using XML literals so that I didn't have to escape out all the quote characters.
Requires Imports System.Text.RegularExpressions
I need your help, guys! :|
I've got myself a CSV file with the following contents:
1,The Compact,1.8GHz,1024MB,160GB,440
2,The Medium,2.4GHz,1024MB,180GB,500
3,The Workhorse,2.4GHz,2048MB,220GB,650
It's a list of computer systems, basically, that the user can purchase.
I need to read this file, line-by-line, into an array. Let's call this array csvline().
The first line of the text file would stored in csvline(0). Line two would be stored in csvline(1). And so on. (I've started with zero because that's where VB starts its arrays). A drop-down list would then enable the user to select 1, 2 or 3 (or however many lines/systems are stored in the file). Upon selecting a number - say, 1 - csvline(0) would be displayed inside a textbox (textbox1, let's say). If 2 was selected, csvline(1) would be displayed, and so on.
It's not the formatting I need help with, though; that's the easy part. I just need someone to help teach me how to read a CSV file line-by-line, putting each line into a string array - csvlines(count) - then increment count by one so that the next line is read into another slot.
So far, I've been able to paste the numbers of each system into an combobox:
Using csvfileparser As New Microsoft.VisualBasic.FileIO.TextFieldParser _
("F:\folder\programname\programname\bin\Debug\systems.csv")
Dim csvalue As String()
csvfileparser.TextFieldType = Microsoft.VisualBasic.FileIO.FieldType.Delimited
csvfileparser.Delimiters = New String() {","}
While Not csvfileparser.EndOfData
csvalue = csvfileparser.ReadFields()
combobox1.Items.Add(String.Format("{1}{0}", _
Environment.NewLine, _
csvalue(0)))
End While
End Using
But this only selects individual values. I need to figure out how selecting one of these numbers in the combobox can trigger textbox1 to be appended with just that line (I can handle the formatting, using the string.format stuff). If I try to do this using csvalue = csvtranslator.ReadLine , I get the following error message:
"Error 1 Value of type 'String' cannot be converted to '1-dimensional array of String'."
If I then put it as an array, ie: csvalue() = csvtranslator.ReadLine , I then get a different error message:
"Error 1 Number of indices is less than the number of dimensions of the indexed array."
What's the knack, guys? I've spent hours trying to figure this out.
Please go easy on me - and keep any responses ultra-simple for my newbie brain - I'm very new to all this programming malarkey and just starting out! :)
Structure systemstructure
Dim number As Byte
Dim name As String
Dim procspeed As String
Dim ram As String
Dim harddrive As String
Dim price As Integer
End Structure
Private Sub csvmanagement()
Dim systemspecs As New systemstructure
Using csvparser As New FileIO.TextFieldParser _
("F:\folder\programname\programname\bin\Debug\systems.csv")
Dim csvalue As String()
csvparser.TextFieldType = Microsoft.VisualBasic.FileIO.FieldType.Delimited
csvparser.Delimiters = New String() {","}
csvalue = csvparser.ReadFields()
systemspecs.number = csvalue(0)
systemspecs.name = csvalue(1)
systemspecs.procspeed = csvalue(2)
systemspecs.ram = csvalue(3)
systemspecs.harddrive = csvalue(4)
systemspecs.optical = csvalue(5)
systemspecs.graphics = csvalue(6)
systemspecs.audio = csvalue(7)
systemspecs.monitor = csvalue(8)
systemspecs.software = csvalue(9)
systemspecs.price = csvalue(10)
While Not csvparser.EndOfData
csvalue = csvparser.ReadFields()
systemlist.Items.Add(systemspecs)
End While
End Using
End Sub
Edit:
Thanks for your help guys, I've managed to solve the problem now.
It was merely a matter calling loops at the right point in time.
I would recommend using FileHelpers to do the reading.
The binding shouldn't be an issue after that.
Here is the Quickstart for Delimited Records:
Dim engine As New FileHelperEngine(GetType( Customer))
// To Read Use:
Dim res As Customer() = DirectCast(engine.ReadFile("FileIn.txt"), Customer())
// To Write Use:
engine.WriteFile("FileOut.txt", res)
When you get the file read, put it into a normal class and just bind to the class or use the list of items you have to do custom stuff with the combobox. Basically, get it out of the file and into a real class asap, then things will be easier.
At least take a look at the library. After using it, we use a lot more simple flat files since it is so easy, and we haven't written a file access routine since (for that kinda stuff).
http://msdn.microsoft.com/en-us/library/microsoft.visualbasic.fileio.textfieldparser.aspx
I think your main problem is understanding how arrays work (hence the error message).
You can use split and join functions to convert strings into and out of arrays
dim s() as string = split("1,2,3",",") gives and array of strings with 3 elements
dim ss as string = join(s,",") gives you the string back
Firstly, it's actually really good that you are using the TextFieldParser for reading CSV files - most don't but you won't have to worry about extra commas and quoted text etc...
The Readline method only gives you the raw string, hence the "Error 1 Value of type 'String' cannot be converted to '1-dimensional array of String'."
What you may find easier with combo boxes etc is to use an object (e.g. 'systemspecs') rather than strings. Assign the CSV data to the objects and override the "ToString" method of the 'systemspecs' class to display in the combo box how you want with formatting etc. That way when you handle the SelectedIndexChanged event (or similar) you get the "SelectedItem" from the combo box (which can be Nothing so check) and cast it as the 'systemspecs' to use it. The advantage is that you are not restricted to display the exact data in the combo etc.
' in "systemspecs"...
Public Overrides Function ToString() As String
Return Name ' or whatever...
End Function ' ToString
e.g.
dim item as new systemspecs
item.ID = csvalue(1)
item.Name = csvalue(2)
' etc...
combobox1.Items.Add(item)
Let me know if that makes sense!
PK :-)