Alphanumeric

[vbgladiator]

Hey,

How can I check whether a character is alphanumeric??

I know I can check the ASC value and compare it, but are there any other ways?

Thanks,

[Wokawidget]

Public Function IAlphaNum(ByVal pstrChar   As String) As Boolean
   Select Case Asc(pstrCar)
      Case vbKey0 To vbKey9
         IsAlphaNum = True
      Case vbKeyA To vbKeyZ 
         IsAlphaNum = True
   End Select
End function

Woka

[MartinLiss]

You can combine the two Cases. I also fixed a couple of typos and added the UCase so that it would work for lowercase as well as uppercase letters.

Public Function IsAlphaNum(ByVal pstrChar As String) As Boolean
   Select Case Asc(UCase(pstrChar))
      Case vbKey0 To vbKey9, vbKeyA To vbKeyZ
         IsAlphaNum = True
   End Select
End Function

[jim mcnamara]

IF you need to repeat this function a lot you can try something like this which is usually faster then SELECT CASE:

Const  IS_DIG as Byte = 2
Const  IS_UPP as Byte =4
Const  IS_LOW as Byte	= 8

Function isalnum(c as Byte) as Byte
    isalnum= ( c + 1) AND ( IS_DIG OR IS_UPP OR IS_LOW) 
End Function

-- note I did this from memory, I believe the const declarations are correct. AND OR operations are faster than other compare operations.

[MartinLiss]

That would sure call for some coments in the code! Can you explain how it works?