VBASorting

Introduction

Unlike the .NET framework, the Visual Basic for Applications library does not include routines to sort arrays.

There are two types of workarounds: 1) implementing a sorting algorithm from scratch, or 2) using sorting routines in other commonly-available libraries.

Algorithm Implementation - Quick Sort on a One-Dimensional Array

From VBA array sort function?

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

Using the Excel Library to Sort a One-Dimensional Array

This code takes advantage of the Sort class in the Microsoft Excel Object Library.

For further reading, see:

Sub testExcelSort()

Dim arr As Variant

InitArray arr
ExcelSort arr

End Sub

Private Sub InitArray(arr As Variant)

Const size = 10
ReDim arr(size)

Dim i As Integer

' Add descending numbers to the array to start
For i = 0 To size
    arr(i) = size - i
Next i

End Sub

Private Sub ExcelSort(arr As Variant)

' Ininitialize the Excel objects (required)
Dim xl As New Excel.Application
Dim wbk As Workbook
Set wbk = xl.Workbooks.Add
Dim sht As Worksheet
Set sht = wbk.ActiveSheet

' Copy the array to the Range object
Dim rng As Range
Set rng = sht.Range("A1")
Set rng = rng.Resize(UBound(arr, 1), 1)
rng.Value = xl.WorksheetFunction.Transpose(arr)

' Run the worksheet's sort routine on the Range
Dim MySort As Sort
Set MySort = sht.Sort
    
With MySort
    .SortFields.Clear
    .SortFields.Add rng, xlSortOnValues, xlAscending, xlSortNormal
    .SetRange rng
    .Header = xlNo
    .Apply
End With

' Copy the results back to the array
CopyRangeToArray rng, arr

' Clear the objects
Set rng = Nothing
wbk.Close False
xl.Quit

End Sub

Private Sub CopyRangeToArray(rng As Range, arr)

Dim i As Long
Dim c As Range

' Can't just set the array to Range.value (adds a dimension)
For Each c In rng.Cells
    arr(i) = c.Value
    i = i + 1
Next c

End Sub