Troubleshooting File Copying and Removing Items in Visual Basic Function

[phion]

Hi,

I'm having trouble figuring out how to copy the contents of a file over to another file, and removing an item of the content of the list I'm copying in the process. The idea is that I need to remove an item from a list by copying everything that is in file one over to file two that is not the item I need to remove, deleting the original file, and the renaming the second file to the original. I can't seem to get it to work.

Here's the function that main calls.

Function removePlayer(playerList() As String, numPlayers As Integer) As Integer
        Dim updatedPlayers As Integer
        Dim player As String
        Dim fileName As String = "playerList.txt"
        Dim tempFileName As String = "tempPlayerList.txt"
        Dim inFile As New StreamReader(fileName)
        Dim outFile As New StreamWriter(tempFileName)

        Console.WriteLine("Which player would you like to remove?")

        player = Console.ReadLine()

        While Not inFile.EndOfStream

            For i = 0 To numPlayers - 1

                playerList(i) = inFile.ReadLine()

                If playerList(i) <> player Then

                    outFile.WriteLine(playerList(i))

                End If

            Next

        End While

        inFile.Close()
        outFile.Close()

        File.Delete("playerList.txt")

        My.Computer.FileSystem.RenameFile("C:\Users\John\Desktop\addPLayerList\bin\Debug\tempPlayerList.txt", "playerList.txt")

        File.Create("C:\Users\John\Desktop\addPLayerList\bin\Debug\tempPlayerList.txt")

        updatedPlayers = numPlayers - 1

        Return updatedPlayers
    End Function

 

[phinds]

"Doesn't work" is a useless characterization of what you are experiencing. OK, it doesn't do what you want. Fine. What DOES it do? What are the symptoms of the error?

 

[Andrew Mason]

The problem may be with the use of <> for strings.

Rather than use "If playerList(i) <> player Then" you might use:

x = Instr(playerList(i), player)
if x = 0 then
outFile.WriteLine(playerList(i))
endif

You might also want to ensure that all strings are put to the same case (ucs or lcs) when comparing.

AM

 

[phion]

"Doesn't work" is a useless characterization of what you are experiencing. OK, it doesn't do what you want. Fine. What DOES it do? What are the symptoms of the error?

It doesn't effectively delete an item from the list, but what it does do is copy the whole list to a temporary file, delete the original, and rename the temporary file to the original name. I need it to leave out the item to be deleted when it copies the list over to the new file.

 

[phinds]

It doesn't effectively delete an item from the list, but what it does do is copy the whole list to a temporary file, delete the original, and rename the temporary file to the original name. I need it to leave out the item to be deleted when it copies the list over to the new file.

Then clearly, your test "playerList(i) <> player" isn't doing what you want. Are you sure you are typing in EXACTLY what is in the line you want to get rid of? Case matters.

 

[phion]

Then clearly, your test "playerList(i) <> player" isn't doing what you want. Are you sure you are typing in EXACTLY what is in the line you want to get rid of? Case matters.

Now what it's doing is deleting the last item in the list regardless of what name I specify to be deleted. Strange.

 

[phinds]

Now what it's doing is deleting the last item in the list regardless of what name I specify to be deleted. Strange.

Are you saying that it is now deleting the one you want AND the last one or just the last one? PLEASE be exact when you are describing these conditions. Trying to guess what you mean is annoying.

 

[phion]

Are you saying that it is now deleting the one you want AND the last one or just the last one? PLEASE be exact when you are describing these conditions. Trying to guess what you mean is annoying.

It's only deleting the last item in the list, no matter what item I want deleted.

 

[phinds]

Sounds like you are passing a number that tells it to read one less than you want it to read plus whatever is causing it to not delete the one you type in.

 

[Andrew Mason]

If you could provide us with a sample of playerList.txt we might have a better idea.

It is deleting the last line because you are starting at 0 instead of 1. Try starting at 1.

To figure out why it is treating as true: playerList(i) <> player when playerList(i) = player you just have to display these variables and see what it is doing. Just insert a msgbox line eg:

For i = 1 To numPlayers

playerList(i) = inFile.ReadLine()
msgbox("playerList(" & i ") = " & playerList(i) & " ; player = " & player)

If playerList(i) <> player Then
msgbox("Printing playerList(" & i ") = " playerList(i))
outFile.WriteLine(playerList(i))

End If​

Next​

Also: it is not clear how you determine numPlayers. Why not just let the for loop continue until you reach the end of the infile?

AM

 

[phion]

playerList.txt displays a simple list of names that the user has input.

John
Tim
Sara
Alex

Then the program will ask, if the user chooses, which name they would like to remove from the list. If I choose, say, John to be removed the list becomes

John
Tim
Sara

When it should be

Tim
Sara
Alex

 

[phion]

Also: it is not clear how you determine numPlayers. Why not just let the for loop continue until you reach the end of the infile?

numPlayers is assigned in a different function where the user adds the players to the list.

I tried just using the for loop and what happens is that every name on the list gets replaced with the name I want to remove.

 

[Andrew Mason]

playerList.txt displays a simple list of names that the user has input.

John
Tim
Sara
Alex

In addition to starting at i=1, You should make sure the comparison is case indifferent. You should also make sure there are no leading or trailing spaces:

dim uplayer as string
dim uplayerlist as string
...
uplayer = UCase(player)
uplayer=Trim(uplayer)

For i = 1 To numPlayers

playerList(i) = inFile.ReadLine()
uplayerlist= UCase(playerList(i))
uplayerlist = Trim(uplayerlist)

If uplayerlist <> uplayer Then
outFile.WriteLine(playerList(i))

End If

Next​

Again, you should make sure that the number of lines in the input file does not exceed numPlayers. To avoid a problem with that you can just keep reading lines until you reach the end of file.

AM

 

[phion]

It's still not doing what I need it to. Here's what I have, it's a small part of a bigger program.

Imports System.IO

Module Module1

    Sub Main()
        Const SIZE As Integer = 50
        Dim playerList(SIZE), tempPlayerList(SIZE) As String
        Dim numPlayers As Integer

        numPlayers = loadList(playerList)

        numPlayers = addPlayers(playerList, numPlayers)

        displayList(playerList, numPlayers)

        numPlayers = removePlayer(playerList, numPlayers)

        displayList(playerList, numPlayers)

        saveList(playerList, numPlayers)

        Console.WriteLine("List saved successfully!")

    End Sub

    Function loadList(playerList() As String) As Integer
        Dim numPlayers As Integer
        Dim fileName As String = "playerList.txt"

        numPlayers = 0

        If File.Exists(fileName) Then

            Dim inFile As New StreamReader(fileName)

            While Not inFile.EndOfStream

                playerList(numPlayers) = inFile.ReadLine()

                numPlayers += 1

            End While

            inFile.Close()

        Else
            Console.WriteLine("Could Not Open " & fileName)
        End If

        Return numPlayers
    End Function

    Function addPlayers(playerList() As String, numPlayers As Integer) As Integer
        Dim newPlayer As String

        Console.Write("Enter player name ('exit' to quit): ")

        newPlayer = Console.ReadLine()

        While newPlayer <> "exit"

            playerList(numPlayers) = newPlayer

            numPlayers += 1

            Console.Write("Enter player name ('exit' to quit): ")

            newPlayer = Console.ReadLine()

        End While

        Return numPlayers

    End Function

    Sub displayList(playerList() As String, numPlayers As Integer)
        Dim i As Integer

        For i = 0 To numPlayers - 1

            Console.WriteLine("Player " & i + 1 & ": " & playerList(i))

        Next

    End Sub

    Function removePlayer(playerList() As String, numPlayers As Integer) As Integer
        Dim updatedPlayers As Integer
        Dim player As String
        Dim fileName As String = "playerList.txt"
        Dim tempFileName As String = "tempPlayerList.txt"
        Dim inFile As New StreamReader(fileName)
        Dim outFile As New StreamWriter(tempFileName)

        Console.WriteLine("Which player would you like to remove?")

        player = Console.ReadLine()

        For i = 1 To numPlayers

            playerList(i) = inFile.ReadLine()

            If player <> playerList(i) Then

                outFile.WriteLine(playerList(i))

            End If

        Next

        inFile.Close()
        outFile.Close()

        File.Delete("playerList.txt")

        My.Computer.FileSystem.RenameFile("C:\Users\John\Desktop\addPLayerList\bin\Debug\tempPlayerList.txt", "playerList.txt")

        File.Create("C:\Users\John\Desktop\addPLayerList\bin\Debug\tempPlayerList.txt")

        updatedPlayers = numPlayers - 1

        Return updatedPlayers
    End Function

    Sub saveList(playerList() As String, numPlayers As Integer)
        Dim fileName As String = "playerList.txt"
        Dim outFile As New StreamWriter(fileName)

        For i = 0 To numPlayers - 1

            outFile.WriteLine(playerList(i))

        Next

        outFile.Close()
    End Sub

End Module

This code works just as I need it to, except when I try to remove a player. I tried taking out the while loop and only using a for loop, but it still just replaces every name with the name I want to remove. I'm careful to use the right cases so I'm not too worried about that part just yet.

 

[mfb]

I don't get the logic:
loadList reads in a file and puts the player list into an array "playerList".
addPlayers modifies this array: it adds an element.
displayList prints out the array.
saveList saves the array. All consistent so far.
removePlayer does not care about the existing array at all, it reads the file again and processes it.

Your array seems to begin at zero (see saveList and displayList), so you should start at zero in your loop.

This code (your last post) replaces entries with the input? Then something odd happens with outFile.WriteLine(playerList(i)). Did you check what is stored at playerList(i) at that point?
What happens if you use a player name (to be removed) not present in the list?
Does saveList work properly?

 

[phion]

I don't get the logic:
loadList reads in a file and puts the player list into an array "playerList".
addPlayers modifies this array: it adds an element.
displayList prints out the array.
saveList saves the array. All consistent so far.
removePlayer does not care about the existing array at all, it reads the file again and processes it.

Your array seems to begin at zero (see saveList and displayList), so you should start at zero in your loop.

This code (your last post) replaces entries with the input? Then something odd happens with outFile.WriteLine(playerList(i)). Did you check what is stored at playerList(i) at that point?
What happens if you use a player name (to be removed) not present in the list?
Does saveList work properly?

Save list works fine. Using a name not on the list actually causes every name except the first to be removed. This is weird.

I set the starting index back to 0 and it's just deleting everything after the first name again. I simply don't understand.

 

[mfb]

Okay, your outFile.WriteLine() does something weird.
What happens if you replace it by outFile.WriteLine("Test")?

 

[Andrew Mason]

While Not inFile.EndOfStream

playerList(numPlayers) = inFile.ReadLine()

numPlayers += 1

End While

I thought numPlayers was a fixed number ie. that does not change. What you appear to be trying to do here is use it as an index.

I am not familiar with the numPlayers += 1 statement. Is it supposed to increment by 1 every iteration, starting at 1? If it does not do that the index will be wrong.

AM

 

[Samy_A]

I have to agree with @mfb , the logic of the program is strange.

    Sub Main()
        Const SIZE As Integer = 50
        Dim playerList(SIZE), tempPlayerList(SIZE) As String
        Dim numPlayers As Integer

        numPlayers = loadList(playerList)

        numPlayers = addPlayers(playerList, numPlayers)

        displayList(playerList, numPlayers)

        numPlayers = removePlayer(playerList, numPlayers)

        displayList(playerList, numPlayers)

        saveList(playerList, numPlayers)

        Console.WriteLine("List saved successfully!")

    End Sub

What your code apparently does:

1. You load a file into the array.
2. You let users add names to that array.
3. You display the array.
4. In removePlayer, you let the user enter a name and then you reload the file (hereby discarding the names added in step 2), fill the array with all the names in the file (including the name the user wants to remove), and save the file with all the names except the one your user chose to remove. However, you loop from 0 to numPlayers-1, where numPlayers is the number of names in the array before you called removePlayer, not necessarily the number of names in the file.
   Then you subtract 1 from numPlayers, irrespective of whether the name to be removed was present in the file or not.
   If I read it correctly, after executing removePlayer, numPlayers wll be one less than the number of names in the array before you called removePlayer.
5. You display the array.
6. You save the array.

These apparent inconsistencies don't explain the results that you get, but certainly don't make debugging this program easier.
It would also help if you could tell us where you see the weird results: is it when you display the array in step 5, or is when you look at the file?

 

[phion]

Since the index of the first element in an array is zero, the for loop starts at zero because that corresponds to the first name in the array.

 

[phion]

It would also help if you could tell us where you see the weird results: is it when you display the array in step 5, or is when you look at the file?

The weird results are apparent when the list is displayed for the second time, after the loop in the removePlayer function has run. When I actually open the file, it contains the list that was displayed the second time, which gets saved successfully. This is a skeleton that is part of a console game I'm writing, and I can't continue with it really until I figure out this strange problem.

Should I turn the arrays into objects? Use a different kind of loop? Discard the text file and only use arrays (which seems even more difficult)?

 

[phion]

Could someone just write a sample piece of code that can do what I need?

 

[Samy_A]

Could someone just write a sample piece of code that can do what I need?

That's not evident as we don't know exactly what the function must do.

Try to separate concerns.
You have a method to read a file into the array, you have a method to save the array into a file.
So don't repeat this in the removePlayer function: call these methods when needed.

If you must read the file in removePlayer, use

While Not inFile.EndOfStream

and not

For i = 0 To numPlayers - 1

, if only because you don't know the number of players while reading the file.

Also address the evident mistakes in removePlayer (as writing all players to the array, including the removed one, or the inconsistencies with the numPlayer counter).
And even if you think that it is not necessary, apply what @Andrew Mason suggested:

You should make sure the comparison is case indifferent. You should also make sure there are no leading or trailing spaces

 

[Andrew Mason]

Do what Samy_A has said. And while you are at try displaying the variables that are being compared (only while you are debugging it - take them out when it is working properly). That is the simplest way to see what the program is doing.

AM

 

[jtbell]

And while you are at try displaying the variables that are being compared (only while you are debugging it - take them out when it is working properly). That is the simplest way to see what the program is doing.

Yes, if you're puzzled by the results of a program not being what you want it to do, don't waste too much time simply staring at the code and trying to guess what it's actually doing. Add some "debug print" statements (or use a debugging tool) so that it tells you what it's actually doing.

 

[phion]

I will have to bone up on my debugging skills. I've stared at this thing for days. I guess what I am hoping for is someone to show me another way to do what I need, possibly using a different syntax or method. It's such a simple task, I don't understand.

 

[Samy_A]

I will have to bone up on my debugging skills. I've stared at this thing for days. I guess what I am hoping for is someone to show me another way to do what I need, possibly using a different syntax or method. It's such a simple task, I don't understand.

We can also stare at this code for days. But you can actually execute it.

So adapt/correct the code as suggested above, and, as also suggested above, add debug.print's (or some other way for actually seeing the value of a variable at a specific point in code execution) when what happens is not what you hoped for.

Don't assume too much, as in: "the mistake can't be here, because that piece of code looks alright". Many bugs you wilI have to deal with will be very trivial and at unexpected locations (at least that is my experience in 30+ years dealing with code).

 

[phion]

(or use a debugging tool)

What's a good debugging tool?

 

[phion]

We can also stare at this code for days. But you can actually execute it.

So adapt/correct the code as suggested above, and, as also suggested above, add debug.print's (or some other way for actually seeing the value of a variable at a specific point in code execution) when what happens is not what you hoped for.

Don't assume too much, as in: "the mistake can't be here, because that piece of code looks alright". Many bugs you wilI have to deal with will be very trivial and at unexpected locations (at least that is my experience in 30+ years dealing with code).

I've only been coding for a few months. While I do enjoy it, my professor dampens my motivation with ruthless grading practices. Thankfully programming is not my major. I didn't even want to learn VB. I was expecting him to teach C++, but whatever.

I'm not even sure where to look for VB debugging tutorials. Any advice?

 

[jtbell]

What's a good debugging tool?

I've never used Visual Basic, so I have no idea. All my programming during the past 25 years or so has been on Unix(ish) systems. I've used gdb occasionally, but normally I use plain old "debug print" statements. Also, I try to develop my programs incrementally, adding one smallish chunk of code at a time and testing it before adding the next chunk.

 

[Samy_A]

I've only been coding for a few months. While I do enjoy it, my professor dampens my motivation with ruthless grading practices. Thankfully programming is not my major. I didn't even want to learn VB. I was expecting him to teach C++, but whatever.

I'm not even sure where to look for VB debugging tutorials. Any advice?

Advice: what @jtbell said. For your problem debug.print or Console.WriteLine should be sufficient. There are more sophisticated debugging tools in Visual Studio, but I don't have any experience with them.

 

[Andrew Mason]

It looks like you are using Visual Studio.net. I am familiar with VB6. The syntax may vary but the concepts are the same. In VB6 the statement: msgbox("caption", datavariablename1, "; caption2: " & datavariablename2 ...etc. ) will stop execution and bring up a message box with the caption and data as it exists at that point in the program. Press "OK" to continue. You will be able to see what is going on. Just comment it out when you figure out what is wrong and get it running.

Is there a reason to dimension an array here? If all you are doing is copying a file and checking it line by line, you don't need to dimension an array. Just do it line by line: input a line from the source file, check it and decide whether to print it and discard or print it to the output file; then get the next line from the source file; continue until end of the source file (use a do/while loop as has been suggested). It is much simpler and a more general way to do it. Just a suggestion.

AM

 

[phion]

It looks like you are using Visual Studio.net. I am familiar with VB6. The syntax may vary but the concepts are the same. In VB6 the statement: msgbox("caption", datavariablename1, "; caption2: " & datavariablename2 ...etc. ) will stop execution and bring up a message box with the caption and data as it exists at that point in the program. Press "OK" to continue. You will be able to see what is going on. Just comment it out when you figure out what is wrong and get it running.

Is there a reason to dimension an array here? If all you are doing is copying a file and checking it line by line, you don't need to dimension an array. Just do it line by line: input a line from the source file, check it and decide whether to print it and discard or print it to the output file; then get the next line from the source file; continue until end of the source file (use a do/while loop as has been suggested). It is much simpler and a more general way to do it. Just a suggestion.

AM

Could you write in code what you mean?

 

[Ibix]

I've only used VBA, but a quick Google suggests that the simple debugging method I use in that ought to work here too.

VB.Net appears to have a "locals" window that will let you see the values of variables. Turn it on: https://msdn.microsoft.com/en-us/library/aa290840(v=vs.71).aspx. Set a simple breakpoint at the beginning of your function (https://msdn.microsoft.com/library/k80ex6de(v=vs.100).aspx). Run your code in debug mode (press F5, apparently). The program pauses when it gets to the instruction where you set the breakpoint. Then you can execute one statement at a time - press F11 to execute one statement (I think: https://msdn.microsoft.com/en-us/library/y740d9d3.aspx. It's F8 in VBA...). Look at the locals window to see what's happening to the variables as you go.

As I say, I've only used that in Excel VBA and I've never used VB.net. Might be worth investigating however - you'll only waste a couple of minutes if it doesn't work, and it's quite powerful if it does work.

 

[phion]

I've only used VBA, but a quick Google suggests that the simple debugging method I use in that ought to work here too.

VB.Net appears to have a "locals" window that will let you see the values of variables. Turn it on: https://msdn.microsoft.com/en-us/library/aa290840(v=vs.71).aspx. Set a simple breakpoint at the beginning of your function (https://msdn.microsoft.com/library/k80ex6de(v=vs.100).aspx). Run your code in debug mode (press F5, apparently). The program pauses when it gets to the instruction where you set the breakpoint. Then you can execute one statement at a time - press F11 to execute one statement (I think: https://msdn.microsoft.com/en-us/library/y740d9d3.aspx. It's F8 in VBA...). Look at the locals window to see what's happening to the variables as you go.

As I say, I've only used that in Excel VBA and I've never used VB.net. Might be worth investigating however - you'll only waste a couple of minutes if it doesn't work, and it's quite powerful if it does work.

I mean, it's pretty clear that the issue resides in the loops I'm using.

Is there a reason to dimension an array here? If all you are doing is copying a file and checking it line by line, you don't need to dimension an array. Just do it line by line: input a line from the source file, check it and decide whether to print it and discard or print it to the output file; then get the next line from the source file; continue until end of the source file (use a do/while loop as has been suggested). It is much simpler and a more general way to do it. Just a suggestion.

AM

When I remove the arrays and the for loop and do as you say, the same exact behavior results. Regardless of the name I type to be removed, the last name in the list is removed instead.

Console.WriteLine("Which player would you like to remove?")

        player = Console.ReadLine()

        While Not inFile.EndOfStream

            copyPlayer = inFile.ReadLine()

            If player <> copyPlayer Then

                outFile.WriteLine(copyPlayer)

            End If

        End While

 

[mfb]

phion, there were so many suggestions to check what happens in the code, why don't you follow them? You keep running the whole code and describing the output with words that can be unclear. That is very inefficient.

 

[Ibix]

I mean, it's pretty clear that the issue resides in the loops I'm using.

When I remove the arrays and the for loop and do as you say, the same exact behavior results. Regardless of the name I type to be removed, the last name in the list is removed instead.

So get the computer to step through the code one instruction at a time. You'll be able to see what's going on in the middle of program execution.

Dumb question - does inFile.ReadLine() strip the newline character? Does Console.ReadLine()? If one is stripping it and one isn't, that would mean that the two strings never match.

 

[phion]

phion, there were so many suggestions to check what happens in the code, why don't you follow them? You keep running the whole code and describing the output with words that can be unclear. That is very inefficient.

I don't know how!

 

[phion]

Dumb question - does inFile.readLine() strip the newline character? Does Console.readLine()?

I couldn't tell you the answer to that, but it seems important.

 

[mfb]

You don't know how to add output to your code? You already have that, just not at the places suggested here.
Using a debugger would be even better, with the descriptions how given above. It is not necessary here, however.

"How to test and debug my code" should be the second step after getting a hello world program running.

 

[Ibix]

I couldn't tell you the answer to that, but it seems important.

Text processing is a pain because of details like this. It may or may not be relevant.

Seriously - open the program you just posted in Visual Studio, display the "locals" window, set a breakpoint on the first line and then step through the program. Each time you go round the loop you'll be able to see what's being read in from the file and see if it is what you expected.

The problem at the moment is that you don't know where to look. There's a bug in there...somewhere. If you step through the program you can see what it's got in memory at the point when something goes wrong. That'll help a lot to tell you why it's going wrong.

 

[TurtleMeister]

Some of your functions are making changes to playerList array. By default Visual Basic passes variables by value. That means that the playerList array in the function is just a copy of the playerList array that was sent in the argument list, and any changes made within the function affect only that copy of the original. When the program exits the function the copy is lost. I'm not sure if this is what's causing the problem you're having, but it appears that some of your functions should be passing the playerList array by reference instead of by value.

 

[Samy_A]

Some of your functions are making changes to playerList array. By default Visual Basic passes variables by value. That means that the playerList array in the function is just a copy of the playerList array that was sent in the argument list, and any changes made within the function affect only that copy of the original. When the program exits the function the copy is lost. I'm not sure if this is what's causing the problem you're having, but it appears that some of your functions should be passing the playerList array by reference instead of by value.

That could be the problem.
It certainly would explain the behavior of removePlayer described at the start of the thread:

Now what it's doing is deleting the last item in the list regardless of what name I specify to be deleted. Strange.

The last item in the list is deleted because he substracts 1 from numPlayers in removePlayers, but the array itself is unchanged..

But it then begs the question why his other methods (that also use the array as a "ByVal" argument) apparently work correctly.

EDIT: Apparently, when you pass an array as argument (even as ByVal), you can still modify the array element apparently.

This means that when you pass a reference type by value, the procedure code has a pointer to the underlying element's data, even though it cannot access the underlying element itself. For example, if the element is an array variable, the procedure code does not have access to the variable itself, but it can access the array members.

And specifically for an array passed "ByVal":

The procedure cannot change the variable but can change members of the instance to which it points.

https://msdn.microsoft.com/en-us/library/eek064h4.aspx

There really is no alternative but for @phion to correct the obvious errors in his code, and then debug the program using one of the techniques mentioned above.

 

[Samy_A]

I mean, it's pretty clear that the issue resides in the loops I'm using.

That may be the case, but don't assume it, debug to make sure.

When I remove the arrays and the for loop and do as you say, the same exact behavior results. Regardless of the name I type to be removed, the last name in the list is removed instead.

Console.WriteLine("Which player would you like to remove?")

        player = Console.ReadLine()

        While Not inFile.EndOfStream

            copyPlayer = inFile.ReadLine()

            If player <> copyPlayer Then

                outFile.WriteLine(copyPlayer)

            End If

        End While

This makes sense. You don't touch your array in this modified code. Now this is not the whole removePlayer function. If your modified version still contains the updatedPlayers = numPlayers - 1 instruction, this will obviously make it appear as if the last name of the array is removed, as you won't reach it when you loop the array.

I know you hope someone here will post a working removePlayer function.
Problem is we don't know what removePlayer is supposed to do exactly: reload the file and remove a name from that list, remove a name from the array already in memory, something else?

What you could do is first clarify for yourself (in words, not in code), what removePlayer is supposed to do exactly.

Then you can adapt your code and start debugging.
One way to debug could be to first hard code the name to be removed instead of using user input. Say the list is "John", "Rita", "Jim", "Alex".
Set the name to be deleted from the list to "Rita". Now run your program and adapt it until it does what you want.
Once it works for "Rita", test if for "John" (first name on the list), "Alex" (last name on the list) and "Samy" (name not on the list). In each case correct the code if it doesn't work.
When you correct the code, don't just try something until it works. Be sure you understand why the program didn't work in this specific case and why your modification will solve the present problem without breaking the code that worked before.

Once you are done with a hard coded name, try it with a name entered by the user. If now it again doesn't work, you have isolated the problem and can deal with it.

 

[Silicon Waffle]

[...]

I'm not even sure where to look for VB debugging tutorials. Any advice?

https://support.microsoft.com/en-us/kb/142999

An array requires a fixed size of a contiguous block of memory. So if the input element number is less than the array size, all the unused elements are assigned to "Nothing" and that (long) block of memory becomes redundant. .
Instead of using arrays, why don't you try out either List (Of String) or ArrayList which is more easy to handle and would free you from such an overhead. You can also use a Collection as in the following code I rewrite for you. This is worse than that being used with either List or ArrayList though.

Module Module1

    Dim numPlayers As Integer
    Dim playerListTmp As New Collection
    Sub Main()
        Dim playerList, tempPlayerList As New Collection()

        numPlayers = loadList(playerList)

        numPlayers = addPlayers(playerList, numPlayers)

        displayList(playerList, numPlayers)

        numPlayers = removePlayer(playerList, numPlayers)

        displayList(playerList, numPlayers)

        saveList(playerList, numPlayers)

        Console.WriteLine("List saved successfully!")

    End Sub

    Function loadList(playerList As Collection
                   ) As Integer

        Dim fileName As String = "playerList.txt"

        numPlayers = 0

        If File.Exists(fileName) Then

            Dim inFile As New StreamReader(fileName)

            While Not inFile.EndOfStream

                playerList.Add(inFile.ReadLine(), numPlayers)

                numPlayers += 1

            End While

            inFile.Close()

        Else
            Console.WriteLine("Could Not Open " & fileName)
        End If

        Return numPlayers
    End Function

    Function addPlayers(playerList As Collection, numPlayers As Integer) As Integer
        Dim newPlayer As String

        Dim fileName As String = "playerList.txt"
        Dim inFile As New StreamWriter(fileName, True)

        Console.Write("Enter player name ('exit' to quit): ")

        newPlayer = Console.ReadLine()

        While newPlayer <> "exit"

            inFile.WriteLine(newPlayer)
            playerList.Add(newPlayer, numPlayers)

            numPlayers += 1

            Console.Write("Enter player name ('exit' to quit): ")

            newPlayer = Console.ReadLine()

        End While
        inFile.Close()
        Return numPlayers

    End Function

    Sub displayList(playerList As Collection, numPlayers As Integer)
        Dim i As Integer
        For i = 1 To numPlayers
            Console.WriteLine("Player " & i & ": " & playerList.Item(i).ToString())
        Next
    End Sub

    Function removePlayer(playerList As Collection, numPlayers As Integer) As Integer
        Dim player As String
        Dim fileName As String = "playerList.txt"
        Dim tempFileName As String = "tempPlayerList.txt"
        Dim inFile As New StreamReader(fileName)
        Dim outFile As New StreamWriter(tempFileName)
        Dim playerTmp As String
        Dim count As Integer = 0

        Console.WriteLine("Which player would you like to remove?")

        player = Console.ReadLine()        For i = 1 To numPlayers

            playerTmp = inFile.ReadLine()

            If player <> playerTmp Then
                playerListTmp.Add(playerTmp, i)
                outFile.WriteLine(playerTmp)
                count += 1
            End If

        Next

        inFile.Close()
        outFile.Close()

        File.Delete("playerList.txt")

        My.Computer.FileSystem.RenameFile("tempPlayerList.txt", "playerList.txt")

        File.Create("tempPlayerList.txt")
        playerList.Clear()
        For i = 1 To count
            playerList.Add(playerListTmp.Item(i), i)
        Next

        Return count
    End Function

    Sub saveList(playerList As Collection, numPlayers As Integer)
        Dim fileName As String = "playerList.txt"
        Dim outFile As New StreamWriter(fileName)

        For i = 1 To numPlayers

            outFile.WriteLine(playerList(i))

        Next

        outFile.Close()
    End SubEnd Module

 

[phion]

What you could do is first clarify for yourself (in words, not in code), what removePlayer is supposed to do exactly.

I'm sorry, I thought this was made clear. This code is for a VB console program designed to manipulate data, namely "wins," "losses," "skill," "name," etc. which are stored in both arrays and text files. The remove player function should modify the playerList text file, and the playerList array I suppose, so that a player specified by the user is removed from the list, as well as all of their other corresponding data stored in separate arrays. This way, when the user chooses the menu option to view records of all the players, the proper data is displayed.

 

[phion]

Ok, I think I just figured it out. I need to sort the list such that the player specified by the user is in the last position of the list before copying over the contents of the file. Does this make sense?

 

[Samy_A]

I'm sorry, I thought this was made clear. This code is for a VB console program designed to manipulate data, namely "wins," "losses," "skill," "name," etc. which are stored in both arrays and text files. The remove player function should modify the playerList text file, and the playerList array I suppose, so that a player specified by the user is removed from the list, as well as all of their other corresponding data stored in separate arrays. This way, when the user chooses the menu option to view records of all the players, the proper data is displayed.

Do you see the ambiguity in your reply? "The remove player function should modify the playerList text file, and the playerList array I suppose".

Your current code doesn't use the array in memory, but reads the file into the array, including the player to be removed. It the saves the list without the removed player to the file (at least that is what it seems to do, but you say it doesn't work).
Try to define precisely what you want removePlayer to do, and then write and test the procedure as has been suggested by a number of people in this thread.

Ok, I think I just figured it out. I need to sort the list such that the player specified by the user is in the last position of the list before copying over the contents of the file. Does this make sense?

Not really, no.
Try to analyze your code and understand why it doesn't do what you want.
Sorting the list with the player in the last position has nothing to do with what you want to achieve or with the reason it doesn't work.

 

[phion]

Do you see the ambiguity in your reply?

Yes, I am aware. You're probably pretty used to customers being frustratingly ambiguous I bet.

I'm working on the others suggestions, but I do feel like keeping this thread alive in the process. Setting breakpoints is something I have not yet done.

 

[Samy_A]

Yes, I am aware. You're probably pretty used to customers being frustratingly ambiguous I bet.

I'm working on the others suggestions, but I do feel like keeping this thread alive in the process. Setting breakpoints is not something I have not yet done.

No problem. Just try to be systematic in your work.