Microsoft KB Archive/133135

= Using a Visual Basic Macro to Sort Arrays in Microsoft Excel =

Article ID: 133135

Article Last Modified on 10/11/2006

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APPLIES TO


 * Microsoft Excel 97 Standard Edition
 * Microsoft Excel 95 Standard Edition
 * Microsoft Excel 5.0 Standard Edition
 * Microsoft Excel 98 for Macintosh

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This article was previously published under Q133135



For a Microsoft Excel 2000 version of this article, see 213818.



SUMMARY
In Microsoft Excel, there is no direct method for sorting an array of values with a Microsoft Visual Basic for Applications macro or procedure. This article discusses two different algorithms that you can use to sort arrays: Selection Sort and Bubble Sort.



MORE INFORMATION
Microsoft provides programming examples for illustration only, without warranty either expressed or implied. This includes, but is not limited to, the implied warranties of merchantability or fitness for a particular purpose. This article assumes that you are familiar with the programming language that is being demonstrated and with the tools that are used to create and to debug procedures. Microsoft support engineers can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific requirements.

Method 1: Selection Sort
To perform a Selection Sort of an array with 1...n elements, locate the largest element from 1...n. If this is not element n, then exchange the largest element with element n. Then, locate the largest element from 1...n-1 and, if this is not element n-1, exchange the largest element with element n-1. Next, locate the largest element from 1...n-2 and, if this is not element n-2, exchange the largest element with element n-2, and so on. Below is an example of a Selection Sort with a Visual Basic Variant type array.

  Type the following in a module sheet: Option Base 1

Function SelectionSort(TempArray As Variant) Dim MaxVal As Variant Dim MaxIndex As Integer Dim i, j As Integer

' Step through the elements in the array starting with the ' last element in the array. For i = UBound(TempArray) To 1 Step -1

' Set MaxVal to the element in the array and save the ' index of this element as MaxIndex. MaxVal = TempArray(i) MaxIndex = i

' Loop through the remaining elements to see if any is             ' larger than MaxVal. If it is then set this element ' to be the new MaxVal. For j = 1 To i                 If TempArray(j) > MaxVal Then MaxVal = TempArray(j) MaxIndex = j                 End If              Next j

' If the index of the largest element is not i, then ' exchange this element with element i.             If MaxIndex < i Then TempArray(MaxIndex) = TempArray(i) TempArray(i) = MaxVal End If         Next i

End Function

Sub SelectionSortMyArray Dim TheArray As Variant

' Create the array. TheArray = Array("one", "two", "three", "four", "five", "six", _             "seven", "eight", "nine", "ten")

' Sort the Array and display the values in order. SelectionSort TheArray For i = 1 To UBound(TheArray) MsgBox TheArray(i) Next i

End Sub  To run the macro, click Macro on the Tools menu. (In Microsoft Excel 97 or Microsoft Excel 98, click the Tools menu, point to Macro, and then click Macros.) Select the SelectionSortMyArray macro, and click Run.

Method 2: Bubble Sort
To perform a Bubble Sort, evaluate 1...n-1 elements in the array where you compare each element with the one after it (element 1 is compared to element 2, element 2 is compared to element 3, and so on). If an element is larger than the element after it, then those two elements are exchanged. Continue this process until there are no more exchanges of elements. Below is an example of a Bubble Sort with a Visual Basic Variant type array.

  Type the following in a module sheet: Option Base 1

Function BubbleSort(TempArray As Variant) Dim Temp As Variant Dim i As Integer Dim NoExchanges As Integer

' Loop until no more "exchanges" are made. Do             NoExchanges = True

' Loop through each element in the array. For i = 1 To UBound(TempArray) - 1

' If the element is greater than the element ' following it, exchange the two elements. If TempArray(i) > TempArray(i + 1) Then NoExchanges = False Temp = TempArray(i) TempArray(i) = TempArray(i + 1) TempArray(i + 1) = Temp End If             Next i          Loop While Not (NoExchanges)

End Function

Sub BubbleSortMyArray Dim TheArray As Variant

' Create the array. TheArray = Array(15, 8, 11, 7, 33, 4, 46, 19, 20, 27, 43, 25, 36)

' Sort the Array and display the values in order. BubbleSort TheArray For i = 1 To UBound(TheArray) MsgBox TheArray(i) Next i     End Sub  To run the macro, click Macro on the Tools menu. (In Microsoft Excel 97 or Microsoft Excel 98, click the Tools menu, point to Macro, and then click Macros.)</li> Select the SelectionSortMyArray macro, and click Run.</li></ol>

NOTE: Both of these examples sort in ascending order. To perform a Selection Sort in descending order, change ">" to "<" in the following line of the SelectionSort function: If TempArray(j) > MaxVal Then To perform a Bubble Sort in descending order, change ">" to a "<" in the following line of the BubbleSort function: If TempArray(i) > TempArray(i + 1) Then

Additional query words: 5.00a 5.00c 8.00 XL98 XL97 XL7 XL5 XL

Keywords: kbdtacode kbhowto kbprogramming KB133135

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