A practical example of evenly distributing n lists into a single list - vba

Question

I had previously asked about how to evenly distribute the items in n lists into a single list and was referred to this question: Good algorithm for combining items from N lists into one with balanced distribution?.
I made a practical example of my solution for this in VBA for Excel, since my application for this was resorting my Spotify lists which can be easily pasted into Excel for manipulation. Assumptions are that you have a headerless worksheet (wsSource) of songs with columns A, B, C representing Artist, Song, SpotifyURI respectively, a "Totals" worksheet (wsTotals) containing the sum of songs for each Artist from wsSource sorted in descending order, and a "Destination" worksheet where the new list will be created. Could I get some suggestions to improve this? I was going to get rid of the totals worksheet and have this portion done in code, but I have to go and I wanted to go ahead and put this out there. Thanks!
Sub WeaveSort()
Dim wb As Workbook
Dim wsDest As Worksheet
Dim wsSource As Worksheet
Dim wsTotals As Worksheet
Dim i As Integer
Dim iLast As Integer
Dim iDest As Integer
Dim iSource As Integer
Dim iOldRow As Integer
Dim iNewRow As Integer
Dim dDiff As Double
Dim dDiffSum As Double
Set wb = ThisWorkbook
Set wsTotals = wb.Worksheets("Totals")
Set wsSource = wb.Worksheets("Source")
Set wsDest = wb.Worksheets("Dest")
iLast = wsTotals.Range("A1").End(xlDown).Row - 1
For i = 2 To iLast
iSource = wsTotals.Range("B" & i).Value
iDest = wsDest.Range("A99999").End(xlUp).Row
If i = 2 Then
wsDest.Range("A1:C" & iSource).Value2 = wsSource.Range("A1:C" & iSource).Value2
wsSource.Range("A1:C" & iSource).Delete (xlShiftUp)
GoTo NextI
End If
dDiff = iDest / iSource
dDiffSum = 0
iNewRow = 0
For iOldRow = 1 To iSource
dDiff = iDest / iSource
dDiffSum = dDiffSum + dDiff
iNewRow = Round(dDiffSum, 0)
wsSource.Rows(iOldRow).Copy
wsDest.Rows(iNewRow).Insert xlShiftDown
iDest = iDest + 1
Next iOldRow
wsSource.Range("A1:C" & iSource).Delete (xlShiftUp)
NextI:
Next i
End Sub

Answer 1

Great question! I would take an object oritentated approach. Also I didn;t think it was clear what the logic was so here is my answer. Two classes and one normal module. Save these separately with the filenames ListManager.cls, List.cls, tstListManager.bas
So the ListManager.cls is this
VERSION 1.0 CLASS
BEGIN
MultiUse = -1 'True
END
Attribute VB_Name = "ListManager"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Option Explicit
Private mdic As Object
Public Sub Initialise(ByVal vLists As Variant)
Set mdic = VBA.CreateObject("Scripting.Dictionary")
Dim vListLoop As Variant
For Each vListLoop In vLists
Dim oList As List
Set oList = New List
oList.Initialise vListLoop, ""
mdic.Add mdic.Count, oList
Next
End Sub
Public Function WeaveSort() As Variant
Dim dicReturn As Object
Set dicReturn = VBA.CreateObject("Scripting.Dictionary")
Dim oNextList As List
Set oNextList = Me.WhichListHasLeastProgress
While oNextList.PercentageDone <= 1
Dim vListItem As Variant
vListItem = oNextList.GetListItem
dicReturn.Add dicReturn.Count, vListItem
oNextList.MoveNext
Set oNextList = Me.WhichListHasLeastProgress
Wend
Dim vItems As Variant
vItems = dicReturn.Items
'I don't like this bit
ReDim vRet(1 To dicReturn.Count, 1 To 1)
Dim lLoop As Long
For lLoop = 0 To dicReturn.Count - 1
vRet(lLoop + 1, 1) = vItems(lLoop)
Next lLoop
WeaveSort = vRet
End Function
Public Function WhichListHasLeastProgress() As List
Dim vKeyLoop As Variant
Dim oListLoop As List
Dim oLeastProgress As List
For Each vKeyLoop In mdic.keys
Set oListLoop = mdic.Item(vKeyLoop)
If oLeastProgress Is Nothing Then
'nothing to compare yet
Set oLeastProgress = oListLoop
Else
If oListLoop.PercentageDone < oLeastProgress.PercentageDone Then
'definitely take this new candidate
Set oLeastProgress = oListLoop
ElseIf oListLoop.PercentageDone = oLeastProgress.PercentageDone And oListLoop.Size > oListLoop.Size Then
'close thing, both showing equal progress but we should give it to the one with the bigger "queue"
Set oLeastProgress = oListLoop
Else
'no swap
End If
End If
Next
'return the answer
Set WhichListHasLeastProgress = oLeastProgress
End Function
and the List.cls file is
VERSION 1.0 CLASS
BEGIN
MultiUse = -1 'True
END
Attribute VB_Name = "List"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Option Explicit
Private mvList As Variant
Private mlCount As Long
Private mlCursor As Long
Private mvName As Variant
Public Function Initialise(ByRef vList As Variant, ByVal vName As Variant)
Debug.Assert TypeName(vList(1, 1)) <> "" ' this will break unless you specify a 2d array
Debug.Assert LBound(vList, 1) = 1 ' this ensure you got it from a sheet
mvList = vList
mlCount = UBound(mvList)
mlCursor = 1
mvName = vName
End Function
Public Function GetListItem()
GetListItem = mvList(mlCursor, 1)
End Function
Public Function Name() As Variant
Name = mvName
End Function
Public Function MoveNext() As Boolean
mlCursor = mlCursor + 1
MoveNext = (mlCursor < mlCount)
End Function
Public Function Size() As Long
Size = mlCount
End Function
Public Function PercentageDone() As Double
PercentageDone = mlCursor / mlCount
End Function
The last file is this tstListManager.bas
Attribute VB_Name = "tstListManager"
Option Explicit
Sub test()
Dim oListMan As ListManager
Set oListMan = New ListManager
Dim vLists As Variant
vLists = VBA.Array(ThisWorkbook.Sheets("Source").Range("A1:A3").Value2, _
ThisWorkbook.Sheets("Source").Range("B1:B2").Value2, _
ThisWorkbook.Sheets("Source").Range("C1:C5").Value2)
oListMan.Initialise vLists
Dim vSorted As Variant
vSorted = oListMan.WeaveSort
Dim lTotal As Long
ThisWorkbook.Sheets("Dest").Range("A1").Resize(UBound(vSorted, 1)).Value2 = vSorted
End Sub
Finally, the test data was in A1:A3 B1:B2 C1:C5
You should note I have abstracted away any Excel reading/writing logic and the pure weavesort logic is not cluttered.
Feel free to reject outright. Object orientation can be quite controversial and we think differently. :)