Character Frequency Count

Scott is looking for a way to get a "frequency count" of all the characters in a document. He would like to know how many times each character, ASCII codes 9 through 255, occur. It is possible to use Find and Replace to determine the count of individual characters (simply search for a character in question and then replace it with itself), but such an approach would be tedious, at best, if you needed to do it for 247 different character codes to get the desired information.

Such a task must be done with a macro, but there are several ways to approach it. One way is to write a quick macro that will step through each member of the Character collection, examining each, and assigning that character to one of a number of counters.

Sub CountChars1()
    Dim iCount(0 To 255) As Integer
    Dim i As Integer
    Dim vCharacter As Variant
    Dim sTemp As String

    ' Initialize the array
    For i = 0 To 255
        iCount(i) = 0
    Next i

    ' Fill the array
    For Each oCharacter In ActiveDocument.Characters
       i = Asc(oCharacter)
       iCount(i) = iCount(i) + 1
    Next

    ' Add document for results
    Documents.Add
    Selection.TypeText Text:="ASCII Character Count" & vbCrLf

    ' Only output codes 9 through 255
    For i = 9 To 255
        sTemp = Chr(i)
        If i < 32 Then sTemp = Trim(Str(i))
        sTemp = sTemp & Chr(9) & Trim(Str(iCount(i)))
        sTemp = sTemp & vbCrLf
        Selection.TypeText Text:=sTemp
    Next i
End Sub

The macro uses the iCount array to accumulate the counts of each character code, and then a new document is created to output the results. (The results document can be formatted in any way desired.)

This approach can work well for relatively short documents, up to a few pages. When the document gets longer, the macro gets slower. Why? Because it takes a great deal of time to use the Characters collection for some reason. If the macro runs too slow for your documents, then you will want to change it a bit so that it works solely with strings.

Sub CountChars2()
    Dim iCount(0 To 255) As Long
    Dim i As Long
    Dim j as integer
    Dim lCharCount As Long
    Dim sDoc As String
    Dim sTemp As String

    ' Initialize the array
    For i = 0 To 255
        iCount(i) = 0
    Next i

    ' Assign document to a huge string
    lCharCount = ActiveDocument.Characters.Count
    sDoc = ActiveDocument.Range(0, lCharCount)

    ' Fill the array
    For i = 1 to Len(sDoc)
       j = Asc(Mid(sDoc, i, 1))
       iCount(j) = iCount(j) + 1
    Next

    ' Add document for results
    Documents.Add
    Selection.TypeText Text:="ASCII Character Count" & vbCrLf

    ' Only output codes 9 through 255
    For i = 9 To 255
        sTemp = Chr(i)
        If i < 32 Then sTemp = Trim(Str(i))
        sTemp = sTemp & Chr(9) & Trim(Str(iCount(i)))
        sTemp = sTemp & vbCrLf
        Selection.TypeText Text:=sTemp
    Next i
End Sub

Notice that this version of the macro stuffs the entire document into a single string, sDoc. This string can then be processed very, very quickly by the macro. (A 635-page document only took about 30 seconds to process on my system.) Because this version is made to work with longer documents, note as well that some of the variable types have been changed to reflect the likelihood of larger counts.