select case [RESOLVED]

[Andy]

If you need to use a select case statement and you want to determine the value of the first few characters of a string, is there a way to 'include' a range rather than using 'or' statments?

ex:

Select Case true
            Case Node.StartsWith("N25") Or _
                      Node.StartsWith("N30") Or _
                      Node.StartsWith("N35") Or _
                      Node.StartsWith("N40") Or _
                      Node.StartsWith("N45")
                Return "192.168.4.237"
 
            Case Node.StartsWith("N55") Or _
                      Node.StartsWith("N65") Or _
                      Node.StartsWith("N70") Or _
                      Node.StartsWith("N50")
                Return "192.168.4.235"
 
            Case Node.StartsWith("N95") Or _
                  Node.StartsWith("N75") Or _
                  Node.StartsWith("N80") Or _
                  Node.StartsWith("N85") Or _
                  Node.StartsWith("N90") Or _
                  Node.StartsWith("N100") Or _
                  Node.StartsWith("N105")
                Return "192.168.4.239"
 
 
        End Select

here, I'm checking for a 'prefix' and it returns an ip address. is there a better way to write that?

[Andy]

alright, I came up with this:

Private Function Server(ByVal Node As String) As String
        'This needs to determine what ip address to connect
        Dim prefix As String = Node.Substring(0, 3)
 
        Select Case prefix
 
            Case "N25", "N30", "N35", "N40", "N45"
                Return "192.168.4.237"
 
            Case "N55", "N65", "N70", "N50"
                Return "192.168.4.235"
 
            Case "N95", "N75", "N80", "N85", "N90", "N100", "N105"
                Return "192.168.4.239"
 
 
        End Select
 
 
    End Function

is that the best way? will that even work?

[Andy]

any comments on this?

[SuperSparks]

That should work just fine, I've done it that way many times.

[VBCrazyCoder]

I have also done that (but shy away from the Select Case true). Also, you don't need to instantiate a new variable - prefix - just do (at least you should be able to do):

Select Case Node.Substring(0, 3)

[taxes]

Hi,

Just a few unenlightened comments.

If prefix is going to contain 3 characters, you can't search for N100 or N105.

For tidiness, you could leave out the "N" from Prefix as it is always there and you can leave out "192.168.4." from the Return and add it later.

If you do leave out the "N" and set prefix to the following 3 characters, you could amend your Case statements for under 100 to include a wildcard

I have never succeeded in using Select Case to compare more than 2 arguments per case (but I have not tried what you are doing)

[dogfish227]

you could do somehting like this

Private Function Server(ByVal Node As String) As String
        'This needs to determine what ip address to connect
        Dim prefix As Integer = cint(Node.Substring(1, 3))
 
        Select Case prefix
 
            Case 25 to 45
                Return "192.168.4.237"
 
            Case 50 to 70
                Return "192.168.4.235"
 
            Case 75 to 105
                Return "192.168.4.239"
 
 
        End Select
 
 
    End Function

that should work so long as the fourth charactor in the node.substring is not a letter. (for the two digit numbers)

[wossname]

Learn how to use "Regular Expressions" (Regex) which is perfect for this kind of processing. Regex Classes are part of the .Net framework. There's loads of stuff in MSDN and check out this book:

"Mastering Regular Expressions" - O'Reilly

Great book.

[taxes]

Hi dogfish227,

"that should work so long as the fourth charactor in the node.substring is not a letter. (for the two digit numbers)"


I think it will ONLY work for two digit numbers if the fourth character IS a letter