Excel VBA Place values in multidimensional array

Question

I have a worksheet with this type of structure (there are more columns in the real sheet, but not many):

ColumnAValue1   ColumnBValue1   23
ColumnAValue1   C         


        

Answer 1

Sub Test()
  Dim c As Collection
  Set c = New Collection

  Dim ws As Worksheet
  Set ws = ThisWorkbook.Worksheets("Sheet1")

  Dim i As Long
  For i = 1 To 10 'Assume 10 rows
    AddToLayeredCollection c, ws.Cells(i, 3).value, ws.Cells(i, 1).value, ws.Cells(i, 2).value 'Assume two columns for keys, A and B
  Next

  'Add 'c' to the watch window and examine it
End Sub

Public Sub AddToLayeredCollection(ByVal root_collection As Collection, ByVal value As Variant, ParamArray keys() As Variant)
  Dim i As Long
  Dim target_collection As Collection

  Set target_collection = root_collection
  For i = LBound(keys) To UBound(keys)
    Set target_collection = ResolveToCollection(target_collection, keys(i))
  Next

  target_collection.Add value
End Sub

Private Function ResolveToCollection(ByVal parent_collection As Collection, ByVal key As Variant) As Collection
  On Error Resume Next
  Set ResolveToCollection = parent_collection(key)(1)
  On Error GoTo 0

  If ResolveToCollection Is Nothing Then
    Set ResolveToCollection = New Collection
    parent_collection.Add Array(key, ResolveToCollection), key
  End If
End Function

The only reason I'm using the Array() thing is to be able to retrieve keys from the collection. You can use Dictionary instead and remove the Array().