Using a Visual Basic Macro to Sort Arrays in Microsoft Excel (133135)

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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.

1. 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
   						

2. 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.)
3. 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.

1. 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
   						

2. 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.)
3. Select the SelectionSortMyArray macro, and click Run.

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