[AccessD] Remove non-alphanumeric characters

Hi Chris

> I have a requirement to strip a string of all non-alphanumeric characters.
> In addition I wanted to change all upper-case characters to lower-case. I
> could not find any ready-rolled solution so I've come up with the code
> below.

> Can anyone think of a more simple way of doing this?

I don't think so. However, if you are about to handle large strings,
the appending method will prove very slow. If this is the case, you
could use Mid() as in the function below which trims a string for
anything else than numerals - you will be able to cut it down and
modify it for your purpose quite easily.

/gustav

<code>

Function TrimNumString( _
  ByVal strNumString As String, _
  Optional ByVal strDecimalChr As String, _
  Optional ByVal booAcceptMinus As Boolean) _
  As String

' Removes any non-numeric character from strNumString including hexadecimal characters.
' If strDecimalChr is specified, first occurrence of this is not removed.
' If booAcceptMinus is True, a leading or trailing minus sign is accepted.
'
' 1999-08-27. Cactus Data ApS, CPH.
' 2001-06-21. Speed optimized for large string (64 K).
' 2003-12-10. intOffset changed to lngOffset.
  
  Const cbytNeg   As Byte = 45  ' "-"
  
  Dim lngPos      As Long
  Dim lngLen      As Long
  Dim lngOffset   As Long
  Dim booDec      As Boolean
  Dim booNeg      As Boolean
  Dim bytChr      As Byte
  Dim bytDec      As Byte
  Dim strNum      As String
  
  strNumString = Trim(strNumString)
  lngLen = Len(strNumString)
  If lngLen > 0 Then
    If Len(strDecimalChr) > 0 Then
      bytDec = Asc(strDecimalChr)
    End If
    ' Create empty result string of maximum possible length.
    strNum = Space(lngLen)
    
    For lngPos = 1 To lngLen
      bytChr = Asc(Mid(strNumString, lngPos, 1))
      Select Case bytChr
        Case 48 To 57
          ' Digit.
        Case bytDec
          ' Decimal point.
          If booDec = False Then
            ' One decimal point only.
            booDec = True
          End If
        Case cbytNeg
          ' Minus sign.
          bytChr = 0
          If booAcceptMinus = True And booNeg = False Then
            If Len(Trim(strNum)) = 0 Or lngPos = lngLen Then
              bytChr = cbytNeg
              ' One minus sign only.
              booNeg = True
            End If
          End If
        Case Else
          ' Ignore any other character.
          bytChr = 0
      End Select
      If bytChr > 0 Then
        ' Append accepted character by inserting it in result string.
        lngOffset = lngOffset + 1
        Mid(strNum, lngOffset) = Chr(bytChr)
      End If
    Next
  End If
  
  ' Trim and return result string.
  TrimNumString = Left(strNum, lngOffset)

End Function

</code>