| CorArray: SortKey |
Sorts an entire array based on an array of keys. An optionally supplied comparer object can be used to compare special elements, such as userdefined values.
Public Sub SortKey( ByRef Keys As Variant, ByRef Items As Variant, Optional ByRef Comparer As Variant )
The Comparer parameter can be an IComparer interface or a callback address to a compare function using the AddressOf method. The callback method signature is defined as follows:
Public Function SortCallback(ByRef x As <Type>, ByRef y As <Type>) As Long
' return less than zero if x is less than y.
' return greater than zero if x is greater than y.
' return zero if x equals y.
End Function
The <Type> the type of element of the array. If the
array is an array of Variants, then <Type> would be a Variant, not
any specific sub-type within the variant elements of the array.
This example demonstrates how an array can be sorted by using another array to determine the sort order for the original. This demonstration uses an array of type vbLong as the keys to sort the main Values array. Even though Values is a vbString type array, it will follow the Keys array when being sorted. Once the array is sorted using the Keys vbLong array, the Values array is displayed to show how the array did not sort using string text compare. The Values array is then sorted again using the standard sort method on the Values vbString type array and re-displayed. This will show the difference between sorting using a Keys array of a different type to sort an original array and how the original array itself would be sorted on its own.
Private Sub Main() Dim Values(14) As String Dim Keys(14) As Long ' Fill both arrays with random values. FillKeysAndValues Keys, Values ' Display the current order of the values array. DisplayValues "Unsorted Values Array.", Values ' Sort the values array using the keys array ' to determine the sort order. CorArray.SortKey Keys, Values ' Display the new sorted values array. ' The values are sorted numerically because the ' keys array is a numeric array. DisplayValues t("\nSorted Values array using Keys array for sort order."), Values ' Re-sort the values array by itself. ' The values are sorted as strings. CorArray.Sort Values ' Display the re-sorted values array, showing ' the how string comparing affects sort order. DisplayValues t("\nRe-sorted Values array using standard sorting with String compares."), Values End Sub ' Fill Keys and Values array. Private Sub FillKeysAndValues(ByRef Keys() As Long, ByRef Values() As String) Dim i As Long Rnd -13 For i = LBound(Keys) To UBound(Keys) Keys(i) = Rnd * i Values(i) = "Value " & Keys(i) Next i End Sub ' Display Array Private Sub DisplayValues(ByVal Title As String, ByRef Values() As String) Dim i As Long Debug.Print Title For i = LBound(Values) To UBound(Values) Debug.Print CorString.Format(" Values({0}) = {1}", i, Values(i)) Next i End Sub ' This code produces the following output. ' ' Unsorted Values Array. ' Values(0) = Value 0 ' Values(1) = Value 0 ' Values(2) = Value 0 ' Values(3) = Value 1 ' Values(4) = Value 4 ' Values(5) = Value 3 ' Values(6) = Value 1 ' Values(7) = Value 0 ' Values(8) = Value 3 ' Values(9) = Value 8 ' Values(10) = Value 8 ' Values(11) = Value 8 ' Values(12) = Value 10 ' Values(13) = Value 10 ' Values(14) = Value 6 ' ' Sorted Values array using Keys array for sort order. ' Values(0) = Value 0 ' Values(1) = Value 0 ' Values(2) = Value 0 ' Values(3) = Value 0 ' Values(4) = Value 1 ' Values(5) = Value 1 ' Values(6) = Value 3 ' Values(7) = Value 3 ' Values(8) = Value 4 ' Values(9) = Value 6 ' Values(10) = Value 8 ' Values(11) = Value 8 ' Values(12) = Value 8 ' Values(13) = Value 10 ' Values(14) = Value 10 ' ' Re-sorted Values array using standard sorting with String compares. ' Values(0) = Value 0 ' Values(1) = Value 0 ' Values(2) = Value 0 ' Values(3) = Value 0 ' Values(4) = Value 1 ' Values(5) = Value 1 ' Values(6) = Value 10 ' Values(7) = Value 10 ' Values(8) = Value 3 ' Values(9) = Value 3 ' Values(10) = Value 4 ' Values(11) = Value 6 ' Values(12) = Value 8 ' Values(13) = Value 8 ' Values(14) = Value 8