Reading the contents of a file into an array

GeorgieMPorgie

I'm trying to read the contents of a file into an array, but for some reason the values are showing up in the array as nothing? The contents of the file look like this (the file length is about 5,690 lines long)

AA.CSV
AAAGY.CSV
AABC.CSV
AACB.CSV

This is the section of code I have written to attempt to do this

'Read the stock symbols to be copied to a new folder into an array

    Dim stocksymbolarrayLong(25000) As String
    Dim filecount As Integer
    Dim counter As Integer

    'Count the lines in the file you are reviewing.

    Dim LongFile As System.IO.StreamReader
    LongFile = System.IO.File.OpenText("C:\\Users\\George Desktop\\Documents\\Stock System\\Stock Programs\\Stock Program Data\\LongStockTesting.txt")

    filecount = 0

    Do Until LongFile.Peek = -1
        LongFile.ReadLine()
        filecount = filecount + 1
    Loop

    For counter = 0 To (filecount - 1)
        stocksymbolarrayLong(counter) = Val(LongFile.ReadLine)
    Next

    LongFile.Close()

    ReDim Preserve stocksymbolarrayLong(filecount - 1)

    ' Sort the array's

    Array.Sort(stocksymbolarrayLong)

This should be very simple to do and solve, but i've been looking at it for a couple hours and don't know what I'm doing wrong? Can someone help?

George

Luc Pattyn

is this VB6 or VB.NET? how many times can you "read to the end"? why do you read the file twice? you could extract and store the required data and find out the number of lines in one go (and your problem would suddenly disappear). if VB.NET, why don't you use a List of Something rather than an array (whose dimension is an implicit limitation to your program)? And are you familiar with File.ReadAllText? File.ReadAllLines? :)

Luc Pattyn [My Articles] Nil Volentibus Arduum

GeorgieMPorgie

Luc, thanks for your prompt reply. Below are my replies to your questions. I'm using VB.NET I'm not sure I understand what you mean "read to end"? I read the file twice. Once to get the length and once to read the data. I'm aware I could do it all at once, but I guess it's just poor form on my part. Not sure how this would make the "problem disappear". The reason I don't use a list is I'm not familiar with lists and how they work. I am also not familiar with file.readalltext and fileradalllines. I'll look them up. Please keep in mind I'm not someone who writes a lot of programs and has a lot of experience. I know there are better ways to accomplish what I am looking to do, but I'm curious as to why what I'm doing isn't working?

George

Dave Kreskowiak

I would seriously read the documentation on List(Of T). It's FAR more flexible than a normal array. You can rewrite your snippet to three lines of code (not including any error handling):

Dim stockSymbols As New List(Of String)
stockSymbols.AddRange(File.ReadAllLines("C:\\Users\\G..."))
stockSymbols.Sort()

A guide to posting questions on CodeProject[^]
Dave Kreskowiak

GeorgieMPorgie

Thanks a lot for the feedback (and education). This is so much easier than what I was doing. :thumbsup:

George

Lost User

GeorgieMPorgie wrote:

I'm curious as to why what I'm doing isn't working?

What does the computer say when you try to run it? Something about your reader?

GeorgieMPorgie wrote:

I'll look them up.

Just curious, did you? The example[^] in the documentation on the method that Luc pointed you to actually shows that it can be done in a single line;

Dim readText() As String = File.ReadAllLines(path)

Bastard Programmer from Hell :suss:

Luc Pattyn

I'm afraid you still haven't figured out why it failed the way you did it. You opened a file, then had a loop reading all its contents (till Peek fails), en then another loop supposed to read all content again. However you never told the file it should restart at the beginning (the again was in your mind, not in your code), so your second loop starts at the end of the file (where it had left off when the first loop ended) and then obviously finds nothing more. To restart a file, either close and open it again, or simply set its Position to zero. So either do it yourself (as you tried) but do it correctly, or use what is available to tackle the most popular situations, such as File.ReadAllLines(). Quite often, less code also means fewer bugs. :)

Luc Pattyn [My Articles] Nil Volentibus Arduum

GeorgieMPorgie

Thank you for explaining what my error was because (as you mention) I never did understand why it didn't work. I actually rewrote my program using file.readalllines() and used a list instead of an array. Thanks again for helping out. Not only did I get an answer to my original question, but I actually learned a better way to get my desired result.

George

GeorgieMPorgie

Eddy, I didn't get an error result and no message about my reader. Yes I did look up lists and file.readalllines(). Learned a lot today from some very kind people. I'll probably end up rewriting a few other programs using what I learned.

George

Lost User

Cool :thumbsup:

Bastard Programmer from Hell :suss:

proneal

Dim stocksymbolarrayLong() As String
Dim filecount As Integer
'Count the lines in the file you are reviewing.

Dim LongFile As System.IO.StreamReader
LongFile = System.IO.File.OpenText("C:\Users\George Desktop\Documents\Stock System\Stock Programs\Stock Program Data\LongStockTesting.txt")

filecount = 0

Do Until LongFile.Peek = -1
LongFile.ReadLine()
ReDim Preserve stocksymbolarrayLong(filecount)
stocksymbolarrayLong(filecount) = LongFile.ReadLine
filecount = filecount + 1
Loop

LongFile.Close()
' Sort the array's
If Not stocksymbolarrayLong Is Nothing Then
Array.Sort(stocksymbolarrayLong)
End If

I did a little reworking USING your method of getting the values. There is better one, readALlLines from the IO.File class, but I used ur code. This should work , but I can't test it. Good luck!

Luc Pattyn

Did you send that to the intended person? I wasn't expecting any help, I was only offering some. :confused:

Luc Pattyn [My Articles] Nil Volentibus Arduum

proneal

Yes, I am sorry -it looks like I replied under wrong heading. My post is intended for OP, and not you in any way. Y_our resolution is what I would have done too, btw_ ;) .Thanks for letting me clear this up. :) have a Great Day Luc!

proneal

Well, who I was meaning to refer to regarding readALLLines method-was the poster that offered up the ReadALlLines method of the File class. - Still, you offered a great help explaining why OP code was failing. That was a good response. :)

Luc Pattyn

Thanks. :)

Luc Pattyn [My Articles] Nil Volentibus Arduum

frostcox

Hey I'd uses a streamreader. so store your csv file in a variable and read it in a using statement using streamreader and set your array = reader.split(',') or ('/t') depending on what format your csv file is in.

GeorgieMPorgie

Thanks for the feedback.

George