Cases for a String [RESOLVED]

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!

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

This code should produce the desired results:

VB Code:

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)

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.

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...

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

Quote:

---

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... :ehh:

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

you can resolve this by declaring the string as

VB Code:

Dim sMessage As String = ""

Sorry,

VB Code:

Dim sGreet As String = ""

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...

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 :)

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

VB Code:

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 :D

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

VB Code:

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)