Cases for a String [RESOLVED]

[LITHIA]

Hi,

It looks like im on a kinda post madness episode here, but I have a lot of questions for the program i am making.

Here's the situation.

When I receive some text from my client, it gets put into a string.

Now, I need some pretty hefty checking in the string. As the text is being written by a user, the server needs to be able to interprete what the user is trying to say to some degree.

Now, first of all i would need to know if you could do this with cases... could you give the same response to several different strings?

Because like "Hello" "Hiya" "Hey" " Hi" have all the same meaning, and i would like to give one response.

So could something like
Case "Hello" Or "Hiya" Or "Hey" Or "Hi"
work? Or how would i go about doing that? I have never used Cases before, and i am going from the examples here.

And also, after i have that sorted, there may be a bit more of a prob. The string isn't going to be EXACTLY one of those responses.

The user could have put a space before " Hello" like that, or after it, so doing a definite lookup won't help. The user might even say "Hello mate" instead, so i need it to recognize a single word within a sentence like this.

At later times, i will make it more advanced but i need help at this stage on just getting the fundamentals down.

So I'll really appreciate any insight on this, as i am kind of stuck of what to do to make it react like i want it.

Thanks very much!

[mendhak]

1. Use Trim to remove trailing and leading spaces.

2. Create a list of "hello" type words, like

hiya,
yo,
heyya,
hey,
hi,
hiiiiii
OMMMGGG!!!!!!!!! HIIIII!!!!!!!! LOLOLO!!!!!!!!!!1111111111111

and when you receive the string from the client, run a loop in this list, checking for each word in the string. Stop when you do.

3. Use Instr() to check if a word exists in a string.



HTH

[CyberHawke]

This code should produce the desired results:

Dim sMessage As String = "Hello world!" 'Sorry, I just had to :D
        Dim sWords() As String
        Dim sDict() As String = "hi,hey,hiya,hello,howdy".Split(",")
        Dim sGreet As String
        Dim wIdx As Int32
        Dim dIdx As Int32
        sWords = sMessage.ToLower.Split(" ")
        For wIdx = sWords.GetLowerBound(0) To sWords.GetUpperBound(0)
            For dIdx = sDict.GetLowerBound(0) To sDict.GetUpperBound(0)
                If sWords(wIdx) = sDict(dIdx) Then
                    sGreet = sWords(wIdx)
                    Exit For
                End If
            Next
            If sGreet.Length > 0 Then Exit For
        Next
        If sGreet.Length > 0 Then MessageBox.Show(sGreet)

[Briantcva]

Probably want to start reading up on regular expressions (System.Text.RegularExpressions). I think that's going to be your answer for anything more complex than "hello" variations.

[LITHIA]

thanks for the quick replies!

Cyberhawke, your code is great - it does exactly what i want it to.

but theres one prob. When the message received is not equal to one of the things in sDict, it gives an error:

Object reference not set to an instance of an object.

Now... thats really strange... it highlights this:
If sGreet.Length > 0
from line
If sGreet.Length > 0 Then Exit For

Do you have any idea why it would do that? I'm totally confused...

[PT Exorcist]

It's because it's not pointing to any string

[LITHIA]

Originally posted by PT Exorcist
It's because it's not pointing to any string

but why...? i thought it was pointing at:

Dim sGreet As String

but its acting as though its not... so why isn't it? I don't understand this... it will be obvious when you say lol, i just don't see it right now...

[PT Exorcist]

It's pointing to it but unlike vb6, when you declare a string it doesnt point to "" by default. If you look with attention to your code you will see that in some situations your string will point to nothing

[CyberHawke]

you can resolve this by declaring the string as

Dim sMessage As String = ""

[CyberHawke]

Sorry,

Dim sGreet As String = ""

[CyberHawke]

Btw: Briantcva

I was doing some investegation into your suggestion about regular expressions. I was not familiar with this until I read your posting. It is definitely worth some research, I believe it has the potential to be a better solution than the one I posted.

Thanks for the info...

[LITHIA]

ah yeah!!! thanks! works now, i should have realised about the 'nothing' as i even put my cursor over it in debug and it said nothing... lol, i just didnt click.

thanks very much for the help guys, and thanks for the code cyberhawke

[LITHIA]

here's the ending code, with option strict on:

Dim sMessage As String = e.Message.Text
        Dim sWords() As String
        Dim sDict() As String = "hi,hey,hiya,hello,howdy".Split(",".ToCharArray)
        Dim sGreet As String = ""
        Dim wIdx As Int32
        Dim dIdx As Int32
        sWords = sMessage.ToLower.Split(" ".ToCharArray)
        For wIdx = sWords.GetLowerBound(0) To sWords.GetUpperBound(0)
            For dIdx = sDict.GetLowerBound(0) To sDict.GetUpperBound(0)
                If sWords(wIdx) = sDict(dIdx) Then
                    sGreet = sWords(wIdx)
                    Exit For
                End If
            Next
            If sGreet.Length > 0 Then Exit For
        Next
        If sGreet.Length > 0 Then MessageBox.Show(sGreet)

e.Message.Text is the message that gets received from the client

[CyberHawke]

Not bad, but I wouldn't bother with the additional variable:

Dim sWords() As String
        Dim sDict() As String = "hi,hey,hiya,hello,howdy".Split(",".ToCharArray)
        Dim sGreet As String = ""
        Dim wIdx As Int32
        Dim dIdx As Int32
        sWords = e.Message.Text.ToLower.Split(" ".ToCharArray)
        For wIdx = sWords.GetLowerBound(0) To sWords.GetUpperBound(0)
            For dIdx = sDict.GetLowerBound(0) To sDict.GetUpperBound(0)
                If sWords(wIdx) = sDict(dIdx) Then
                    sGreet = sWords(wIdx)
                    Exit For
                End If
            Next
            If sGreet.Length > 0 Then Exit For
        Next
        If sGreet.Length > 0 Then MessageBox.Show(sGreet)