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.

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Answer 1

This is what I use to sort in memory - it can easily be expanded to sort an array.

Sub sortlist()

    Dim xarr As Variant
    Dim yarr As Variant
    Dim zarr As Variant

    xarr = Sheets("sheet").Range("sing col range")
    ReDim yarr(1 To UBound(xarr), 1 To 1)
    ReDim zarr(1 To UBound(xarr), 1 To 1)

    For n = 1 To UBound(xarr)
        zarr(n, 1) = 1
    Next n

    For n = 1 To UBound(xarr) - 1
        y = zarr(n, 1)
        For a = n + 1 To UBound(xarr)
            If xarr(n, 1) > xarr(a, 1) Then
                y = y + 1
            Else
                zarr(a, 1) = zarr(a, 1) + 1
            End If
        Next a
        yarr(y, 1) = xarr(n, 1)
    Next n

    y = zarr(UBound(xarr), 1)
    yarr(y, 1) = xarr(UBound(xarr), 1)

    yrng = "A1:A" & UBound(yarr)
    Sheets("sheet").Range(yrng) = yarr

End Sub

Answer 2

Explanation in German but the code is a well-tested in-place implementation:

Private Sub QuickSort(ByRef Field() As String, ByVal LB As Long, ByVal UB As Long)
    Dim P1 As Long, P2 As Long, Ref As String, TEMP As String

    P1 = LB
    P2 = UB
    Ref = Field((P1 + P2) / 2)

    Do
        Do While (Field(P1) < Ref)
            P1 = P1 + 1
        Loop

        Do While (Field(P2) > Ref)
            P2 = P2 - 1
        Loop

        If P1 <= P2 Then
            TEMP = Field(P1)
            Field(P1) = Field(P2)
            Field(P2) = TEMP

            P1 = P1 + 1
            P2 = P2 - 1
        End If
    Loop Until (P1 > P2)

    If LB < P2 Then Call QuickSort(Field, LB, P2)
    If P1 < UB Then Call QuickSort(Field, P1, UB)
End Sub

Invoked like this:

Call QuickSort(MyArray, LBound(MyArray), UBound(MyArray))

Answer 3

I converted the 'fast quick sort' algorithm to VBA, if anyone else wants it.

I have it optimized to run on an array of Int/Longs but it should be simple to convert it to one that works on arbitrary comparable elements.

Private Sub QuickSort(ByRef a() As Long, ByVal l As Long, ByVal r As Long)
    Dim M As Long, i As Long, j As Long, v As Long
    M = 4

    If ((r - l) > M) Then
        i = (r + l) / 2
        If (a(l) > a(i)) Then swap a, l, i '// Tri-Median Methode!'
        If (a(l) > a(r)) Then swap a, l, r
        If (a(i) > a(r)) Then swap a, i, r

        j = r - 1
        swap a, i, j
        i = l
        v = a(j)
        Do
            Do: i = i + 1: Loop While (a(i) < v)
            Do: j = j - 1: Loop While (a(j) > v)
            If (j < i) Then Exit Do
            swap a, i, j
        Loop
        swap a, i, r - 1
        QuickSort a, l, j
        QuickSort a, i + 1, r
    End If
End Sub

Private Sub swap(ByRef a() As Long, ByVal i As Long, ByVal j As Long)
    Dim T As Long
    T = a(i)
    a(i) = a(j)
    a(j) = T
End Sub

Private Sub InsertionSort(ByRef a(), ByVal lo0 As Long, ByVal hi0 As Long)
    Dim i As Long, j As Long, v As Long

    For i = lo0 + 1 To hi0
        v = a(i)
        j = i
        Do While j > lo0
            If Not a(j - 1) > v Then Exit Do
            a(j) = a(j - 1)
            j = j - 1
        Loop
        a(j) = v
    Next i
End Sub

Public Sub sort(ByRef a() As Long)
    QuickSort a, LBound(a), UBound(a)
    InsertionSort a, LBound(a), UBound(a)
End Sub

Answer 4

Dim arr As Object
Dim InputArray

'Creating a array list
Set arr = CreateObject("System.Collections.ArrayList")

'String
InputArray = Array("d", "c", "b", "a", "f", "e", "g")

'number
'InputArray = Array(6, 5, 3, 4, 2, 1)

' adding the elements in the array to array_list
For Each element In InputArray
    arr.Add element
Next

'sorting happens
arr.Sort

'Converting ArrayList to an array
'so now a sorted array of elements is stored in the array sorted_array.

sorted_array = arr.toarray

Answer 5

@Prasand Kumar, here's a complete sort routine based on Prasand's concepts:

Public Sub ArrayListSort(ByRef SortArray As Variant)
    '
    'Uses the sort capabilities of a System.Collections.ArrayList object to sort an array of values of any simple
    'data-type.
    '
    'AUTHOR: Peter Straton
    '
    'CREDIT: Derived from Prasand Kumar's post at: https://stackoverflow.com/questions/152319/vba-array-sort-function
    '
    '*************************************************************************************************************

    Static ArrayListObj As Object
    Dim i As Long
    Dim LBnd As Long
    Dim UBnd As Long

    LBnd = LBound(SortArray)
    UBnd = UBound(SortArray)

    'If necessary, create the ArrayList object, to be used to sort the specified array's values

    If ArrayListObj Is Nothing Then
        Set ArrayListObj = CreateObject("System.Collections.ArrayList")
    Else
        ArrayListObj.Clear  'Already allocated so just clear any old contents
    End If

    'Add the ArrayList elements from the array of values to be sorted. (There appears to be no way to do this
    'using a single assignment statement.)

    For i = LBnd To UBnd
        ArrayListObj.Add SortArray(i)
    Next i

    ArrayListObj.Sort   'Do the sort

    'Transfer the sorted ArrayList values back to the original array, which can be done with a single assignment
    'statement.  But the result is always zero-based so then, if necessary, adjust the resulting array to match
    'its original index base.

    SortArray = ArrayListObj.ToArray
    If LBnd <> 0 Then ReDim Preserve SortArray(LBnd To UBnd)
End Sub

Answer 6

Natural Number (Strings) Quick Sort

Just to pile onto the topic. Normally, if you sort strings with numbers you'll get something like this:

    Text1
    Text10
    Text100
    Text11
    Text2
    Text20

But you really want it to recognize the numerical values and be sorted like

    Text1
    Text2
    Text10
    Text11
    Text20
    Text100

Here's how to do it...

Note:

• I stole the Quick Sort from the internet a long time ago, not sure where now...
• I translated the CompareNaturalNum function which was originally written in C from the internet as well.
• Difference from other Q-Sorts: I don't swap the values if the BottomTemp = TopTemp

Natural Number Quick Sort

Public Sub QuickSortNaturalNum(strArray() As String, intBottom As Integer, intTop As Integer)
Dim strPivot As String, strTemp As String
Dim intBottomTemp As Integer, intTopTemp As Integer

    intBottomTemp = intBottom
    intTopTemp = intTop

    strPivot = strArray((intBottom + intTop) \ 2)

    Do While (intBottomTemp <= intTopTemp)
        ' < comparison of the values is a descending sort
        Do While (CompareNaturalNum(strArray(intBottomTemp), strPivot) < 0 And intBottomTemp < intTop)
            intBottomTemp = intBottomTemp + 1
        Loop
        Do While (CompareNaturalNum(strPivot, strArray(intTopTemp)) < 0 And intTopTemp > intBottom) '
            intTopTemp = intTopTemp - 1
        Loop
        If intBottomTemp < intTopTemp Then
            strTemp = strArray(intBottomTemp)
            strArray(intBottomTemp) = strArray(intTopTemp)
            strArray(intTopTemp) = strTemp
        End If
        If intBottomTemp <= intTopTemp Then
            intBottomTemp = intBottomTemp + 1
            intTopTemp = intTopTemp - 1
        End If
    Loop

    'the function calls itself until everything is in good order
    If (intBottom < intTopTemp) Then QuickSortNaturalNum strArray, intBottom, intTopTemp
    If (intBottomTemp < intTop) Then QuickSortNaturalNum strArray, intBottomTemp, intTop
End Sub

Natural Number Compare(Used in Quick Sort)

Function CompareNaturalNum(string1 As Variant, string2 As Variant) As Integer
'string1 is less than string2 -1
'string1 is equal to string2 0
'string1 is greater than string2 1
Dim n1 As Long, n2 As Long
Dim iPosOrig1 As Integer, iPosOrig2 As Integer
Dim iPos1 As Integer, iPos2 As Integer
Dim nOffset1 As Integer, nOffset2 As Integer

    If Not (IsNull(string1) Or IsNull(string2)) Then
        iPos1 = 1
        iPos2 = 1
        Do While iPos1 <= Len(string1)
            If iPos2 > Len(string2) Then
                CompareNaturalNum = 1
                Exit Function
            End If
            If isDigit(string1, iPos1) Then
                If Not isDigit(string2, iPos2) Then
                    CompareNaturalNum = -1
                    Exit Function
                End If
                iPosOrig1 = iPos1
                iPosOrig2 = iPos2
                Do While isDigit(string1, iPos1)
                    iPos1 = iPos1 + 1
                Loop

                Do While isDigit(string2, iPos2)
                    iPos2 = iPos2 + 1
                Loop

                nOffset1 = (iPos1 - iPosOrig1)
                nOffset2 = (iPos2 - iPosOrig2)

                n1 = Val(Mid(string1, iPosOrig1, nOffset1))
                n2 = Val(Mid(string2, iPosOrig2, nOffset2))

                If (n1 < n2) Then
                    CompareNaturalNum = -1
                    Exit Function
                ElseIf (n1 > n2) Then
                    CompareNaturalNum = 1
                    Exit Function
                End If

                ' front padded zeros (put 01 before 1)
                If (n1 = n2) Then
                    If (nOffset1 > nOffset2) Then
                        CompareNaturalNum = -1
                        Exit Function
                    ElseIf (nOffset1 < nOffset2) Then
                        CompareNaturalNum = 1
                        Exit Function
                    End If
                End If
            ElseIf isDigit(string2, iPos2) Then
                CompareNaturalNum = 1
                Exit Function
            Else
                If (Mid(string1, iPos1, 1) < Mid(string2, iPos2, 1)) Then
                    CompareNaturalNum = -1
                    Exit Function
                ElseIf (Mid(string1, iPos1, 1) > Mid(string2, iPos2, 1)) Then
                    CompareNaturalNum = 1
                    Exit Function
                End If

                iPos1 = iPos1 + 1
                iPos2 = iPos2 + 1
            End If
        Loop
        ' Everything was the same so far, check if Len(string2) > Len(String1)
        ' If so, then string1 < string2
        If Len(string2) > Len(string1) Then
            CompareNaturalNum = -1
            Exit Function
        End If
    Else
        If IsNull(string1) And Not IsNull(string2) Then
            CompareNaturalNum = -1
            Exit Function
        ElseIf IsNull(string1) And IsNull(string2) Then
            CompareNaturalNum = 0
            Exit Function
        ElseIf Not IsNull(string1) And IsNull(string2) Then
            CompareNaturalNum = 1
            Exit Function
        End If
    End If
End Function

isDigit(Used in CompareNaturalNum)

Function isDigit(ByVal str As String, pos As Integer) As Boolean
Dim iCode As Integer
    If pos <= Len(str) Then
        iCode = Asc(Mid(str, pos, 1))
        If iCode >= 48 And iCode <= 57 Then isDigit = True
    End If
End Function