Sorting a Two-Dimensional Array using a Bubble Sort
By Darren Neimke
Before you Read this Article...
Before reading this article, it is highly suggested that you read the first part of this article,
Sorting a One-Dimensional Array using a Bubble Sort. This
previous article discussed the intracacies of the Bubble Sort, including a performance comparison
to QuickSort.
Sorting a Two-Dimensional Array with Bubble Sort
This article assumes that you have read my previous article
on Bubble Sort with a one-dimensional array. In this article, we're going to jump into sorting a
two-dimensional array and skip past a lot of the explanation that was presented in the
first article.
First of all let's create a 2-dimensional Array an write it's contents to the screen:
That gives us an unsorted list that looks like this:
Darren - 10
Andrew - 5
Paul - 8
Homer - 2
Bart - 1
Lisa - 7
Barney - 6
Fred - 9
Wilma - 3
Betty - 4
However, with some minor changes to our one dimensional sort routine
we can not only sort our array but also declare with dimension to sort the array by!
The code for this function is presented below, along with a live demo.
Sub DualSorter( byRef arrArray, DimensionToSort )
Dim row, j, StartingKeyValue, StartingOtherValue, _
NewStartingKey, NewStartingOther, _
swap_pos, OtherDimension
Const column = 1
' Ensure that the user has picked a valid DimensionToSort
If DimensionToSort = 1 then
OtherDimension = 0
ElseIf DimensionToSort = 0 then
OtherDimension = 1
Else
'Shoot, invalid value of DimensionToSort
Response.Write "Invalid dimension for DimensionToSort: " & _
"must be value of 1 or 0."
Response.End
End If
For row = 0 To UBound( arrArray, column ) - 1
'Start outer loop.
'Take a snapshot of the first element
'in the array because if there is a
'smaller value elsewhere in the array
'we'll need to do a swap.
StartingKeyValue = arrArray ( row, DimensionToSort )
StartingOtherValue = arrArray ( row, OtherDimension )
' Default the Starting values to the First Record
NewStartingKey = arrArray ( row, DimensionToSort )
NewStartingOther = arrArray ( row, OtherDimension )
swap_pos = row
For j = row + 1 to UBound( arrArray, column )
'Start inner loop.
If arrArray ( j, DimensionToSort ) < NewStartingKey Then
'This is now the lowest number -
'remember it's position.
swap_pos = j
NewStartingKey = arrArray ( j, DimensionToSort )
NewStartingOther = arrArray ( j, OtherDimension )
End If
Next
If swap_pos <> row Then
'If we get here then we are about to do a swap
'within the array.
arrArray ( swap_pos, DimensionToSort ) = StartingKeyValue
arrArray ( swap_pos, OtherDimension ) = StartingOtherValue
arrArray ( row, DimensionToSort ) = NewStartingKey
arrArray ( row, OtherDimension ) = NewStartingOther
End If
Next
End Sub
Now we simply call our routine, passing in our array and the
dimension that we wish to sort by:
call DualSorter(arrDualArray, 1)
Since we are creating a zero-based array, the 1 in the above function call
informs the function to sort the second dimension. If we wanted to sort by the first dimension
we would pass in a 0
And return the results to the screen
For i = LBound(arrDualArray) to UBound(arrDualArray)
Response.Write arrDualArray(i, 0) & " - "
Response.Write arrDualArray(i, 1) & "<BR>"
Next
Gives us the following output. As you can see - problem sorted:
Bart - 1
Homer - 2
Wilma - 3
Betty - 4
Andrew - 5
Barney - 6
Lisa - 7
Paul - 8
Fred - 9
Darren - 10
Now that we've shown how to sort a two-dimensional array of scalar variables, let's look at
how we can sort an array of objects! We'll examine this topic in Part 2
of this article.
