Blonde Moment

[djrmkr]

Does anyone know of a really quick/good sort routine for arrays ??

I.E.
1,4,5,8,6,3
should be
1,3,4,5,6,8

Having a blonde moment and do you think for the life of me I can remember a descent one.

If anyone could help please.

[Lord Orwell]

you could do the "bubble sort" method in which you start at the top and move down comparing 1 to 2, 2 to 3, etc. If 2 is less than 1, swap them and start over. if 3 < 2 swap them and start over. This works really well as long as you dont have thousands of array elements.
When you finally get to the last 2 elements AND THEY DONT HAVE TO BE SWAPPED you are done. else you have to start over.

should be a piece of cake to perform.

Its called bubble sort because the smaller numbers "bubble" up to the top.

[TheSarlacc]

dirs is the array name and numdirs is the number
of elements in the array

'sort dirs
exchange = True
While exchange
exchange = False
For I = 2 To numdirs
If dirs(I - 1) > dirs(I) Then
exchange = True
tmp = dirs(I): dirs(I) = dirs(I - 1): dirs(I - 1) = tmp
End If
Next I
Wend

[djrmkr]

thanks, it might be a bit slow, is there another way to do it?

[Lord Orwell]

memory checks to arrays are surprisingly fast.
Now if you were sorting a listbox, then THAT would be slow.

How many array elements are you expecting to have?

[djrmkr]

About 1.3 million

[Lord Orwell]

ok i'll post a better method tomorrow morning.
I dont have time right now.

[djrmkr]

Thanks.

[Lord Orwell]

ok here is method one designed for large lists.
it will probably still take forever if you have 1.3 million elements though. I always found that when you generate a new add-in to a list it was better to sort the list as you went along.

But here goes.
the following is public domain code typed in from the "Visual Basic 5 from the ground up" reference.

This method is called Merge Sort.
It splits the list into smaller lists (by recursively calling itself), sorts them, then recombines them.

sub Mergesort (a$(), Start as Integer, Finish as Integer
  Dim Middle as Integer
  middle = (Start + Finish) \ 2 'integer result
  MergeSort A$(), Start, Middle
  MergeSort A$(), Start, Middle, Finish
  Merge A$(), Start, Middle, Finish
End if
End Sub

Sub Merge(A$(), Start As Integer, Middle as Integer, Finish as Integer)
'local vars:  Temp$(), Begin1, End1, Begin2, End2,  Templocation1

   ReDim Temp$(Start to Finish)
   Dim Begin1 as Integer, End1 as integer, Begin2 as integer
   Dim End2 as Integer, TempLocation as integer, I as integer
   Begin1 = Start
   End1 = Middle
   Begin2 = End1 + 1
   End2 = Finish
   Templocation = start
   Do While Begin1 <= End1 and begin2 <= end2
     if a$(begin1) <= a$(begin2) then
       Temp$(templocation) = a$(begin1)
       Templocation = templocation + 1
       begin1 = begin1 + 1
     else 
       temp$(templocation) = a$(begin2)
       templocation = templocation + 1
       begin2 = begin2 + 1
     end if
   loop
   if begin1 <= end1 then
      for i = begin1 to end1
        temp$(templocation) = a$(i)
        templocation = templocation + 1
      next i
   elseif begin2 <= end2 then
      for i = begin2 to end2
        temp$(templocation) = a$(i)
        templocation = templocation + 1
      next i
   for i = start to finish
      a$(i) = temp$(i)
   next i
end sub

[plenderj]

Here's a way I just came up with.
It uses the numbers you give as the array indexes in an array.
Then you loop through the array, and if the values at those indexes contain a value, then print it.
Therefore we've just sorted the array ...

Option Explicit

Dim dstArray() As Long
Dim srcArray() As Long
Dim highestSoFar As Long

Private Sub sort(sourceArray() As Long)
    Dim i As Long
    For i = 0 To UBound(sourceArray)
        If (sourceArray(i) > highestSoFar) Then
            ReDim Preserve dstArray(sourceArray(i))
            highestSoFar = sourceArray(i)
        End If
        dstArray(sourceArray(i)) = 1
    Next i
End Sub

Private Sub Command1_Click()
    Dim i As Long
    ReDim dstArray(0)
    ReDim srcArray(0)
    
    'fill the array with random numbers
    For i = 0 To 1000000
        ReDim Preserve srcArray(i)
        srcArray(i) = CLng(Rnd * 100000)
    Next i

    'Now sort the array of values
    sort srcArray()
    
    'Now dstArray() contains a nummerically sorted version or srcArray()
    For i = 1 To UBound(dstArray)
        If (dstArray(i) = 1) Then
            List1.AddItem i
        End If
    Next i
    
    MsgBox "done"
    
End Sub

As far as I can tell it works
And its very fast too ...

- jamie

[billfaceuk]

How do I use that code if I'm populating an array like this?

Dim bFile() As String
Dim gCount As String
Dim v7 As String, v8 As String, v9 As String, i As Integer
gCount = 0
Open "C:\My Documents\Vb5.0\postcodes.txt" For Input As #4
Do Until EOF(4)
Input #4, v7, v8, v9
ReDim Preserve bFile(gCount) As String
bFile(gCount) = v7 + " - " + v8 + " - " + v9
Loop
gCount = gCount + 1
Close #4

[Lord Orwell]

what is postcodes generated by?
and are the values all numeric

[billfaceuk]

it's in this format:

"text","text","number between 1-12"

[rickm]

You could use an ADO Recordset that is not bound to a table. Then it will sort them based on text characteristics. It would be a bit slower than this last bit of code however. If you want to know how, let me know.

Rick