VBA array sort function?

Question

I'm looking for a decent sort implementation for arrays in VBA. A Quicksort would be preferred. Or any other sort algorithm other than bubble or merge would suffice.

Please note that this is to work with MS Project 2003, so should avoid any of the Excel native functions and anything .net related.

Answer 1

Take a look here:
Edit: The referenced source (allexperts.com) has closed, but here's the relevant author comments:

There are many algorithms available on the web for sorting. The most versatile and usually the quickest is the Quicksort algorithm. Below is a function for it.

Call it simply by passing an array of values (string or numeric; it doesn't matter) with the Lower Array Boundary (usually 0) and the Upper Array Boundary (i.e. UBound(myArray).)

Example: Call QuickSort(myArray, 0, UBound(myArray))

When it's done, myArray will be sorted and you can do what you want with it.
_{(Source: archive.org)}

Public Sub QuickSort(vArray As Variant, inLow As Long, inHi As Long)

  Dim pivot   As Variant
  Dim tmpSwap As Variant
  Dim tmpLow  As Long
  Dim tmpHi   As Long

  tmpLow = inLow
  tmpHi = inHi

  pivot = vArray((inLow + inHi) \ 2)

  While (tmpLow <= tmpHi)

     While (vArray(tmpLow) < pivot And tmpLow < inHi)
        tmpLow = tmpLow + 1
     Wend

     While (pivot < vArray(tmpHi) And tmpHi > inLow)
        tmpHi = tmpHi - 1
     Wend

     If (tmpLow <= tmpHi) Then
        tmpSwap = vArray(tmpLow)
        vArray(tmpLow) = vArray(tmpHi)
        vArray(tmpHi) = tmpSwap
        tmpLow = tmpLow + 1
        tmpHi = tmpHi - 1
     End If

  Wend

  If (inLow < tmpHi) Then QuickSort vArray, inLow, tmpHi
  If (tmpLow < inHi) Then QuickSort vArray, tmpLow, inHi

End Sub

Note that this only works with single-dimensional (aka "normal"?) arrays. (There's a working multi-dimensional arraye QuickSort here.)

Answer 2

I posted some code in answer to a related question on StackOverflow:

Sorting a multidimensionnal array in VBA

The code samples in that thread include:

1. A vector array Quicksort;
2. A multi-column array QuickSort;
3. A BubbleSort.

Alain's optimised Quicksort is very shiny: I just did a basic split-and-recurse, but the code sample above has a 'gating' function that cuts down on redundant comparisons of duplicated values. On the other hand, I code for Excel, and there's a bit more in the way of defensive coding - be warned, you'll need it if your array contains the pernicious 'Empty()' variant, which will break your While... Wend comparison operators and trap your code in an infinite loop.

Note that quicksort algorthms - and any recursive algorithm - can fill the stack and crash Excel. If your array has fewer than 1024 members, I'd use a rudimentary BubbleSort.

Public Sub QuickSortArray(ByRef SortArray As Variant, _
                                Optional lngMin As Long = -1, _ 
                                Optional lngMax As Long = -1, _ 
                                Optional lngColumn As Long = 0)
On Error Resume Next

'Sort a 2-Dimensional array

' Sample Usage: sort arrData by the contents of column 3
'
'   QuickSortArray arrData, , , 3

'
'Posted by Jim Rech 10/20/98 Excel.Programming

'Modifications, Nigel Heffernan:

'       ' Escape failed comparison with empty variant
'       ' Defensive coding: check inputs

Dim i           As Long
Dim j           As Long
Dim varMid      As Variant
Dim arrRowTemp  As Variant
Dim lngColTemp  As Long


 If IsEmpty(SortArray) Then
     Exit Sub
 End If

 If InStr(TypeName(SortArray), "()") < 1 Then  'IsArray() is somewhat broken:  Look for brackets in the type name
     Exit Sub
 End If

 If lngMin = -1 Then
     lngMin = LBound(SortArray, 1)
 End If
 
 If lngMax = -1 Then
     lngMax = UBound(SortArray, 1)
 End If
 
 If lngMin >= lngMax Then ' no sorting required
     Exit Sub
 End If


 i = lngMin
 j = lngMax

 varMid = Empty
 varMid = SortArray((lngMin + lngMax) \ 2, lngColumn)

 ' We  send 'Empty' and invalid data items to the end of the list:
 If IsObject(varMid) Then  ' note that we don't check isObject(SortArray(n)) - varMid might pick up a valid default member or property
     i = lngMax
     j = lngMin
 ElseIf IsEmpty(varMid) Then
     i = lngMax
     j = lngMin
 ElseIf IsNull(varMid) Then
     i = lngMax
     j = lngMin
 ElseIf varMid = "" Then
     i = lngMax
     j = lngMin
 ElseIf varType(varMid) = vbError Then
     i = lngMax
     j = lngMin
 ElseIf varType(varMid) > 17 Then
     i = lngMax
     j = lngMin
 End If


 While i <= j

     While SortArray(i, lngColumn) < varMid And i < lngMax
         i = i + 1
     Wend

     While varMid < SortArray(j, lngColumn) And j > lngMin
         j = j - 1
     Wend


     If i <= j Then

         ' Swap the rows
         ReDim arrRowTemp(LBound(SortArray, 2) To UBound(SortArray, 2))
         For lngColTemp = LBound(SortArray, 2) To UBound(SortArray, 2)
             arrRowTemp(lngColTemp) = SortArray(i, lngColTemp)
             SortArray(i, lngColTemp) = SortArray(j, lngColTemp)
             SortArray(j, lngColTemp) = arrRowTemp(lngColTemp)
         Next lngColTemp
         Erase arrRowTemp

         i = i + 1
         j = j - 1

     End If


 Wend

 If (lngMin < j) Then Call QuickSortArray(SortArray, lngMin, j, lngColumn)
 If (i < lngMax) Then Call QuickSortArray(SortArray, i, lngMax, lngColumn)

 
End Sub

Answer 3

You didn't want an Excel-based solution but since I had the same problem today and wanted to test using other Office Applications functions I wrote the function below.

Limitations:

• 2-dimensional arrays;
• maximum of 3 columns as sort keys;
• depends on Excel;

Tested calling Excel 2010 from Visio 2010

---

Option Base 1


Private Function sort_array_2D_excel(array_2D, array_sortkeys, Optional array_sortorders, Optional tag_header As String = "Guess", Optional tag_matchcase As String = "False")

'   Dependencies: Excel; Tools > References > Microsoft Excel [Version] Object Library

    Dim excel_application As Excel.Application
    Dim excel_workbook As Excel.Workbook
    Dim excel_worksheet As Excel.Worksheet

    Set excel_application = CreateObject("Excel.Application")

    excel_application.Visible = True
    excel_application.ScreenUpdating = False
    excel_application.WindowState = xlNormal

    Set excel_workbook = excel_application.Workbooks.Add
    excel_workbook.Activate

    Set excel_worksheet = excel_workbook.Worksheets.Add
    excel_worksheet.Activate
    excel_worksheet.Visible = xlSheetVisible

    Dim excel_range As Excel.Range
    Set excel_range = excel_worksheet.Range("A1").Resize(UBound(array_2D, 1) - LBound(array_2D, 1) + 1, UBound(array_2D, 2) - LBound(array_2D, 2) + 1)
    excel_range = array_2D


    For i_sortkey = LBound(array_sortkeys) To UBound(array_sortkeys)

        If IsNumeric(array_sortkeys(i_sortkey)) Then
            sortkey_range = Chr(array_sortkeys(i_sortkey) + 65 - 1) & "1"
            Set array_sortkeys(i_sortkey) = excel_worksheet.Range(sortkey_range)

        Else
            MsgBox "Error in sortkey parameter:" & vbLf & "array_sortkeys(" & i_sortkey & ") = " & array_sortkeys(i_sortkey) & vbLf & "Terminating..."
            End

        End If

    Next i_sortkey


    For i_sortorder = LBound(array_sortorders) To UBound(array_sortorders)
        Select Case LCase(array_sortorders(i_sortorder))
            Case "asc"
                array_sortorders(i_sortorder) = XlSortOrder.xlAscending
            Case "desc"
                array_sortorders(i_sortorder) = XlSortOrder.xlDescending
            Case Else
                array_sortorders(i_sortorder) = XlSortOrder.xlAscending
        End Select
    Next i_sortorder

    Select Case LCase(tag_header)
        Case "yes"
            tag_header = Excel.xlYes
        Case "no"
            tag_header = Excel.xlNo
        Case "guess"
            tag_header = Excel.xlGuess
        Case Else
            tag_header = Excel.xlGuess
    End Select

    Select Case LCase(tag_matchcase)
        Case "true"
            tag_matchcase = True
        Case "false"
            tag_matchcase = False
        Case Else
            tag_matchcase = False
    End Select


    Select Case (UBound(array_sortkeys) - LBound(array_sortkeys) + 1)
        Case 1
            Call excel_range.Sort(Key1:=array_sortkeys(1), Order1:=array_sortorders(1), Header:=tag_header, MatchCase:=tag_matchcase)
        Case 2
            Call excel_range.Sort(Key1:=array_sortkeys(1), Order1:=array_sortorders(1), Key2:=array_sortkeys(2), Order2:=array_sortorders(2), Header:=tag_header, MatchCase:=tag_matchcase)
        Case 3
            Call excel_range.Sort(Key1:=array_sortkeys(1), Order1:=array_sortorders(1), Key2:=array_sortkeys(2), Order2:=array_sortorders(2), Key3:=array_sortkeys(3), Order3:=array_sortorders(3), Header:=tag_header, MatchCase:=tag_matchcase)
        Case Else
            MsgBox "Error in sortkey parameter:" & vbLf & "Maximum number of sort columns is 3!" & vbLf & "Currently passed: " & (UBound(array_sortkeys) - LBound(array_sortkeys) + 1)
            End
    End Select


    For i_row = 1 To excel_range.Rows.Count

        For i_column = 1 To excel_range.Columns.Count

            array_2D(i_row, i_column) = excel_range(i_row, i_column)

        Next i_column

    Next i_row


    excel_workbook.Close False
    excel_application.Quit

    Set excel_worksheet = Nothing
    Set excel_workbook = Nothing
    Set excel_application = Nothing


    sort_array_2D_excel = array_2D


End Function

---

This is an example on how to test the function:

Private Sub test_sort()

    array_unsorted = dim_sort_array()

    Call msgbox_array(array_unsorted)

    array_sorted = sort_array_2D_excel(array_unsorted, Array(2, 1, 3), Array("desc", "", "asdas"), "yes", "False")

    Call msgbox_array(array_sorted)

End Sub


Private Function dim_sort_array()

    Dim array_unsorted(1 To 5, 1 To 3) As String

    i_row = 0

    i_row = i_row + 1
    array_unsorted(i_row, 1) = "Column1": array_unsorted(i_row, 2) = "Column2": array_unsorted(i_row, 3) = "Column3"

    i_row = i_row + 1
    array_unsorted(i_row, 1) = "OR": array_unsorted(i_row, 2) = "A": array_unsorted(i_row, 3) = array_unsorted(i_row, 1) & "_" & array_unsorted(i_row, 2)

    i_row = i_row + 1
    array_unsorted(i_row, 1) = "XOR": array_unsorted(i_row, 2) = "A": array_unsorted(i_row, 3) = array_unsorted(i_row, 1) & "_" & array_unsorted(i_row, 2)

    i_row = i_row + 1
    array_unsorted(i_row, 1) = "NOT": array_unsorted(i_row, 2) = "B": array_unsorted(i_row, 3) = array_unsorted(i_row, 1) & "_" & array_unsorted(i_row, 2)

    i_row = i_row + 1
    array_unsorted(i_row, 1) = "AND": array_unsorted(i_row, 2) = "A": array_unsorted(i_row, 3) = array_unsorted(i_row, 1) & "_" & array_unsorted(i_row, 2)

    dim_sort_array = array_unsorted

End Function


Sub msgbox_array(array_2D, Optional string_info As String = "2D array content:")

    msgbox_string = string_info & vbLf

    For i_row = LBound(array_2D, 1) To UBound(array_2D, 1)

        msgbox_string = msgbox_string & vbLf & i_row & vbTab

        For i_column = LBound(array_2D, 2) To UBound(array_2D, 2)

            msgbox_string = msgbox_string & array_2D(i_row, i_column) & vbTab

        Next i_column

    Next i_row

    MsgBox msgbox_string

End Sub

---

If anybody tests this using other versions of office please post here if there are any problems.

Answer 4

I think my code (tested) is more "educated", assuming the simpler the better.

Option Base 1

'Function to sort an array decscending
Function SORT(Rango As Range) As Variant
    Dim check As Boolean
    check = True
    If IsNull(Rango) Then
        check = False
    End If
    If check Then
        Application.Volatile
        Dim x() As Variant, n As Double, m As Double, i As Double, j As Double, k As Double
        n = Rango.Rows.Count: m = Rango.Columns.Count: k = n * m
        ReDim x(n, m)
        For i = 1 To n Step 1
            For j = 1 To m Step 1
                x(i, j) = Application.Large(Rango, k)
                k = k - 1
            Next j
        Next i
        SORT = x
    Else
        Exit Function
    End If
End Function