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Sorting an Array with over 2 million members - Analyzing on Excel VBA

I have a vba code which calculates over 2 million numbers and puts them into an array. I want to sort these values inside the array. As far as I can see there is no sort function in excel vba.  
I tried Qsortinplace which can be found http://www.cpearson.com/excel/SortingArrays.aspx .

But it seems it doesnt work when there are 2 million members inside the array.

I guess something can be arranged when filling the array in the first place.

What is the best way to sort the huge arrays?
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dlmille
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Long datatype will support array indexes up to  2,147,483,647.  Will this suffice?

Here's a heapsort algorithm using long (I personally use QuickSort, but wanted something documented with long array indexes, so here it is - untested by me):

http://www.source-code.biz/snippets/vbasic/1.htm

If not, then it can be done with a collection and collection sort.  I can assist with this, but first await your response to the first question, above.

Cheers,

Dave

Actually a variant array may be larger (can't find my reference on that).  Let me see if I can load a variant array with 3 million records using variant arrays and my quicksort algorithm...

Dave
Here's a QuickSort macro I use all the time, I only changed integer to variant.  It SHOULD work, and right now I'm trying to figure out how to load an array with > 1MM records without waiting forever.

Give it and the heapsort a shot, as you're already in a position to test.  Note usage on the Qsort...

Call QSort(myArray, LBound(myArray), UBound(myArray))

Will repaint the variant array myArray in sorted order.  Its easy enough to add a boolean in the mix to determine ascending/descending and I can help with that if you like it.  right now its ascending.

Let me know if this works for you:

 
Sub QSort(sortArray As Variant, ByVal leftIndex As Integer, ByVal rightIndex As Integer)
    Dim compValue As Variant
    Dim i As Variant
    Dim j As Variant
    Dim tempVar As Variant

    i = leftIndex
    j = rightIndex
    
    compValue = sortArray(Int((i + j) / 2))

    Do
        Do While (sortArray(i) < compValue And i < rightIndex)
            i = i + 1
        Loop
        Do While (compValue < sortArray(j) And j > leftIndex)
            j = j - 1
        Loop
        If i <= j Then
        
            tempVar = sortArray(i)
            sortArray(i) = sortArray(j)
            sortArray(j) = tempVar
            
            i = i + 1
            j = j - 1
        End If
    Loop While i <= j

    If leftIndex < j Then QSort sortArray, leftIndex, j
    If i < rightIndex Then QSort sortArray, i, rightIndex
End Sub

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My bad.  I had one type-o in my integer-> variant conversion.

Sorry for the SPAM!

Here's a QuickSort macro I use all the time, I only changed integer to variant.  It SHOULD work, and right now I'm trying to figure out how to load an array with > 1MM records without waiting forever.

Give it and the heapsort a shot, as you're already in a position to test.  Note usage on the Qsort...

Call QSort(myArray, LBound(myArray), UBound(myArray))

Will repaint the variant array myArray in sorted order.  Its easy enough to add a boolean in the mix to determine ascending/descending and I can help with that if you like it.  right now its ascending.

Let me know if this works for you:

 
Sub QSort(sortArray As Variant, ByVal leftIndex As variant, ByVal rightIndex As variant)
    Dim compValue As Variant
    Dim i As Variant
    Dim j As Variant
    Dim tempVar As Variant

    i = leftIndex
    j = rightIndex
    
    compValue = sortArray(Int((i + j) / 2))

    Do
        Do While (sortArray(i) < compValue And i < rightIndex)
            i = i + 1
        Loop
        Do While (compValue < sortArray(j) And j > leftIndex)
            j = j - 1
        Loop
        If i <= j Then
        
            tempVar = sortArray(i)
            sortArray(i) = sortArray(j)
            sortArray(j) = tempVar
            
            i = i + 1
            j = j - 1
        End If
    Loop While i <= j

    If leftIndex < j Then QSort sortArray, leftIndex, j
    If i < rightIndex Then QSort sortArray, i, rightIndex
End Sub

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Avatar of Martin Liss
I think that the thing to do is to not sort 2,000,000 records but rather to create the 'array' sorted as you build it. I have 'array' in single quotes because what I suggest is that you use the VBA Dictionary object instead. It is like a collection but faster. Here is a short tutorial.
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dlmille
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