Array Utilities

Developer: RhinoScript
Summary: Presents an array of VBScript Array utilities.

Arrays are a very useful and easy way of storing variables - and they're especially easy to use in VBScript. This is due to several factors:

• VBScript is particularly liberal with any variable definition - that means that there is no strict defining of variables to a particular data type.
• The data type is assigned automatically when the variable is loaded with a value.
• It is even possible to mix data types within the same array.
• It is also possible to define the arrays in different ways:
  • Create the array element by element.
  • Use the VBScript Array method.
  • Use the VBScript Split method.
  • It is even possible to create multi-dimensional arrays and to make them dynamic rather than static.

But, VBScript falls short, compared to other programming languages, when it comes to providing tools for manipulating arrays. Some common array operations that VBScript does not provide methods for are:

• Adding a new elements to an array.
• Appending one array to the end of another array.
• Inserting new elements at given positions in an array.
• Removing elements from an array.
• Removing duplicate items from an array.
• Sorting the elements in an array.
• Reverse the order of the elements in an array.

For some of these tasks, RhinoScript does provide useful methods.

• CullDuplicateNumbers - Remove duplicates from an array of numbers.
• CullDuplicatePoints - Remove duplicates from an array of 3-D points.
• CullDuplicateStrings - Remove duplicates from an array of strings.
• SortNumbers - Sorts an array of numbers.
• SortPoints - Sorts an array of 3-D points.
• SortStrings - Sorts an array of strings.

For the other tasks, you will need to write your own procedures. Fortunately, VBScript provides us enough tools to write our own procedures to do most of what we would ever want to do with an array. Note, the following examples are general purpose utilities. If you need something more specific, these examples are a good starting point.

 Sub ArrayAdd(ByRef arr, ByVal val)
   Dim ub
   If IsArray(arr) Then
     On Error Resume Next
     ub = UBound(arr)
     If Err.Number <> 0 Then ub = -1
     ReDim Preserve arr(ub + 1)
     arr(UBound(arr)) = val
   End If
 End Sub

 Sub ArrayAppend(ByRef arr, ByVal arr0)
   Dim i, ub
   If IsArray(arr) And IsArray(arr0) Then
     On Error Resume Next
     ub = UBound(arr)
     If Err.Number <> 0 Then ub = -1
     ReDim Preserve arr(ub + UBound(arr0) + 1)
     For i = 0 To UBound(arr0)
       arr(ub + 1 + i) = arr0(i)
     Next
   End If
 End Sub

This example uses the .NET ArrayList object:

 Sub ArrayAppend(ByRef arr, ByVal arr0)
   Dim i, list
   If IsArray(arr) Then
     Set list = CreateObject("System.Collections.ArrayList")
     For i = 0 To UBound(arr)
       Call list.Add(arr(i))
     Next
     For i = 0 To UBound(arr0)
       Call list.Add(arr0(i))
     Next
     arr = list.ToArray()    
   End If
 End Sub

 Sub ArrayInsert(ByRef arr, ByVal pos, ByVal val)
   Dim i
   If IsArray(arr) Then
     If pos > UBound(arr) Then
       Call ArrayAdd(arr, val)
     ElseIf pos >= 0 Then
       ReDim Preserve arr(UBound(arr) + 1)
       For i = UBound(arr) To pos + 1 Step -1
         arr(i) = arr(i - 1)
       Next
       arr(pos) = val
     End If
   End If
 End Sub

This example uses the .NET ArrayList object:

 Sub ArrayInsert(ByRef arr, ByVal pos, ByVal val)
   Dim i, list
   If IsArray(arr) Then
     Set list = CreateObject("System.Collections.ArrayList")
     For i = 0 To UBound(arr)
       Call list.Add(arr(i))
     Next
     Call list.Insert(pos, val)
     arr = list.ToArray()    
   End If
 End Sub

 Sub ArrayRemove(ByRef arr)
   If IsArray(arr) Then
     If UBound(arr) > -1 Then
       ReDim Preserve arr(UBound(arr) - 1)
     End If
   End If
 End Sub

 Sub ArrayRemoveAt(ByRef arr, ByVal pos)
   Dim i
   If IsArray(arr) Then
     If pos >= 0 And pos <= UBound(arr) Then
       For i = pos To UBound(arr) - 1
         arr(i) = arr(i + 1)
       Next
       ReDim Preserve arr(UBound(arr) - 1)
     End If
   End If
 End Sub

This example uses the .NET ArrayList object:

 Sub ArrayRemoveAt(ByRef arr, ByVal pos)
   Dim i, list
   If IsArray(arr) Then
     Set list = CreateObject("System.Collections.ArrayList")
     For i = 0 To UBound(arr)
       Call list.Add(arr(i))
     Next
     Call list.RemoveAt(pos)
     arr = list.ToArray()    
   End If
 End Sub

 Sub ArrayRemoveVal(ByRef arr, ByVal val)
   Dim i, j
   If IsArray(arr) Then
     i = 0 : j = -1
     For i = 0 To UBound(arr)
       If arr(i) <> val Then
         j = j + 1
         arr(j) = arr(i)
       End If
     Next
   ReDim Preserve arr(j)
   End If
 End Sub

This example uses VBScript's Dictionary object:

 Sub ArrayCull(ByRef arr)
   Dim i, dict
   If IsArray(arr) Then
     Set dict = CreateObject("Scripting.Dictionary")
     For i = 0 To UBound(arr)
       If Not dict.Exists(arr(i)) Then
         Call dict.Add(arr(i), arr(i))
       End If
     Next
     arr = dict.Items
   End If 
 End Sub

This example uses the .NET ArrayList object:

 Sub ArrayCull(ByRef arr)
   Dim i, list, tmp
   If IsArray(arr) Then
     Set list = CreateObject("System.Collections.ArrayList")
     For i = 0 To UBound(arr)
       If Not list.Contains(arr(i)) Then
         Call list.Add(arr(i))
       End If
     Next
     arr = list.ToArray()    
   End If
 End Sub

 Function ArraySearch(ByRef arr, ByVal val)
   Dim i
   ArraySearch = -1
   If IsArray(arr) Then
     For i = 0 To UBound(arr)
       If arr(i) = val Then
         ArraySearch = i
         Exit Function
       End If
     Next
   End If
 End Function

This example uses a simple Bubble Sort algorithm:

 Sub ArraySort(ByRef arr)
   Dim i, j, tmp
   If IsArray(arr) Then
     For i = UBound(arrShort) - 1 To 0 Step -1
       For j = 0 To i
         If arr(j) > arr(j + 1) Then
           tmp = arr(j + 1)
           arr(j + 1) = arr(j)
           arr(j) = tmp
         End If
       Next
     Next
   End If
 End Sub

This example uses the .NET ArrayList object:

 Sub ArraySort(ByRef arr)
   Dim i, list
   If IsArray(arr) Then
     Set list = CreateObject("System.Collections.ArrayList")
     For i = 0 To UBound(arr)
       Call list.Add(arr(i))
     Next
     Call list.Sort()
     arr = list.ToArray()
   End If    
 End Sub

 Sub ArrayReverse(ByRef arr)
   Dim i, ub, ub2, tmp
   ub = UBound(arr)
   ub2 = Int(ub / 2)
   For i = 0 To ub2
     tmp = arr(i)
     arr(i) = arr(ub - i)
     arr(ub - i) = tmp
   Next
 End Sub

This example uses the .NET ArrayList object:

 Sub ArrayReverse(ByRef arr)
   Dim i, list
   If IsArray(arr) Then
     Set list = CreateObject("System.Collections.ArrayList")
     For i = 0 To UBound(arr)
       Call list.Add(arr(i))
     Next
     Call list.Reverse()
     arr = list.ToArray()
   End If    
 End Sub

 Function IsArrayDim(ByVal arr)
   IsArrayDim = False
   If IsArray(arr) Then
     On Error Resume Next
     Call UBound(arr)
     If Err.Number = 0 Then IsArrayDim = True
   End If
 End Function

 Public Function GetArrayDim(ByVal arr)
   Dim i
   If IsArray(arr) Then
     For i = 1 To 60
       On Error Resume Next
       Call UBound(arr, i)
       If Err.Number <> 0 Then
         GetArrayDim = i - 1
         Exit Function
       End If
     Next
     GetArrayDim = i
   Else
     GetArrayDim = Null
   End If
 End Function

 Sub ArrayPrint(ByVal arr)
   Dim i
   If IsArray(arr) Then
     For i = 0 To UBound(arr)
       Call Rhino.Print("Item(" & CStr(i) & ") = " & CStr(arr(i)))
     Next
   End If
 End Sub