[AccessD] Count the occurrences of each character in a string

[Stuart McLachlan]

For a Unicode string with potentially thousands of code points, you don't want an array of all 
possible values.

You can do it with an array the same size as the string length
A bit more complicated than the previous code, but this one works well  with either ANSI or 
Unicode strings.


Function Lettercount(sInputString As String, CaseSensitive As Boolean) As Long
    Dim lStr As Long, x As Long, y As Long, compare As Long
    Dim sTxt As String
    Dim freq() As Long

    'Initialise
    sTxt = sInputString 'we are going to modify the string!
    If CaseSensitive = True Then
        compare = vbBinaryCompare
    Else
        compare = vbTextCompare
    End If
    lStr = Len(sTxt)
    ReDim freq(1 To lStr)

    'Get the letter counts
    For x = 1 To lStr
       freq(x) = 1
       For y = x + 1 To lStr
           If StrComp(Mid$(sTxt, x, 1), Mid$(sTxt, y, 1), compare) = 0 Then
               freq(x) = freq(x) + 1
               Mid$(sTxt, y, 1) = Chr$(0)
          End If
       Next
   Next

  'Display the results
   For x = 1 To lStr
      If Mid$(sTxt, x, 1) <> Chr$(0) Then
        Debug.Print Mid$(sTxt, x, 1) & "  -  " & str$(freq(x))
      End If
   Next
End Function




On 5 Sep 2022 at 19:29, Stuart McLachlan wrote:

> Classic  "bucket" or "pigeon hole" application.
> 
> For ANSI strings:
> 
> DIm arr(32 to 255) 'assumes only printable values
> for x = 1 to len(strTest)
>    y = aSC(mid$(strTest,x,1)
>   arr(y) = arr(y) + 1
> next
> for x = 32  to 255
>    if arr(x) > 0 then  debug.print chr$(x) & " - " & str$(arr(x)) next
> 
> 
> If it's a Wide String that can contain any Unicode point,  then you
> really need to use a more complex solution such as a BTree or a
> Collection where you check whether you already have an item with a key
> matching the current character code and either add it or increment its
> value.
> 
> 
> 
> On 5 Sep 2022 at 4:43, Arthur Fuller wrote:
> 
> > I'm trying to figure out the best way to count the occurrences of
> > each character in a string. Sample string: "mississipi" I should get
> > back an array looking like this:
> > 
> > Character Count
> > m 1
> > i 4
> > s 4
> > p 1
> > 
> > Any suggestions?
> > 
> > -- 
> > Arthur
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> > 
> 
> 
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