Visual Basic for Applications/Bubble Sort on One Key

SummaryEdit

This page is intended for procedures that sort on two dimensions. Further, since some make use of multisort methods, this page is restricted to sorting on a single key. That is, using one column or row as the basis of the sort.

Bubble Sort Arrays in VBAEdit

  • The procedure is for sorting a two dimensional array. This is perhaps the most common requirement. The options allow for column or row sorts, choice of sort index, and the choice of ascending or descending sorts. There is again, a choice of returning the sorted work in a different array with the input intact, or if not supplied, returning it with the original changed.
  • The bubble sort's speed is suitable for most VBA projects, though faster sorting algorithms are used for more demanding applications. Although not available for Excel, those who are using MS Word might consider calling the SortArray function of WordBasic instead. In Excel the WorksheetFunctions might bear some study as to their sorting usefulness.

The Code ModuleEdit

Function SortArr2D1Key(ByRef vA As Variant, _
                       Optional ByVal bIsAscending As Boolean = True, _
                       Optional ByVal bIsRowSort As Boolean = True, _
                       Optional ByVal SortIndex As Long = -1, _
                       Optional ByRef vRet As Variant) As Boolean
'--------------------------------------------------------------------------------
' Procedure : SortArr2D1Key
' Purpose   : Bubblesorts a 2D array on 1 key, up or down, on any column or row.
'             Options include in-place, with the source changed, or
'             returned in vRet, with the source array intact.
'             Optional parameters default to: ROW SORT in place, ASCENDING,
'             using COLUMN ONE as the key.
'--------------------------------------------------------------------------------
    
    Dim condition1 As Boolean, vR As Variant
    Dim i As Long, j As Long, y As Long, t As Variant
    Dim loR As Long, hiR As Long, loC As Long, hiC As Long
    Dim r As Long, c As Long, bWasMissing As Boolean
    
    'find bounds of vA data input array
    loR = LBound(vA, 1): hiR = UBound(vA, 1)
    loC = LBound(vA, 2): hiC = UBound(vA, 2)
    
    'find whether optional vR was initially missing
    bWasMissing = IsMissing(vRet)
    'If Not bWasMissing Then Set vRet = Nothing
    
    'check input range of SortIndex
    If bIsRowSort And (SortIndex < loC Or SortIndex > hiC) Then
        MsgBox "SortIndex out of bounds in Sort2DArr; closing now"
        Exit Function
    Else:
    End If
    
    If Not bIsRowSort And (SortIndex < loR Or SortIndex > hiR) Then
        MsgBox "SortIndex out of bounds in Sort2DArr; closing now"
        Exit Function
    Else:
    End If
    
    'pass to a work variable
    vR = vA
    
    'steer input options
    If bIsRowSort Then GoTo ROWSORT Else GoTo COLSORT
    
ROWSORT:
    For i = loR To hiR - 1
        For j = loR To hiR - 1
            If bIsAscending Then
                condition1 = vR(j, SortIndex) > vR(j + 1, SortIndex)
            Else
                condition1 = vR(j, SortIndex) < vR(j + 1, SortIndex)
            End If
            If condition1 Then
                For y = loC To hiC
                    t = vR(j, y)
                    vR(j, y) = vR(j + 1, y)
                    vR(j + 1, y) = t
                Next y
            End If
        Next
    Next
    GoTo TRANSFERS
    
COLSORT:
    For i = loC To hiC - 1
        For j = loC To hiC - 1
            If bIsAscending Then
                condition1 = vR(SortIndex, j) > vR(SortIndex, j + 1)
            Else
                condition1 = vR(SortIndex, j) < vR(SortIndex, j + 1)
            End If
            If condition1 Then
                For y = loR To hiR
                    t = vR(y, j)
                    vR(y, j) = vR(y, j + 1)
                    vR(y, j + 1) = t
                Next y
            End If
        Next
    Next
    GoTo TRANSFERS
    
TRANSFERS:
    'decide whether to return in vA or vRet
    If Not bWasMissing Then
        'vRet was the intended return array
        'so return vRet leaving vA intact
        vRet = vR
    Else:
        'vRet is not intended return array
        'so reload vA with vR
        vA = vR
    End If
    
    'set return function value
    SortArr2D1Key = True
    
End Function