Announcement

**Ian Cairns** · 13 Dec 1999, 10:38 PM

David,

Maybe you don't have to sort Every array to get the desired result.
How about if you just sort one array, and an array of pointers to the data?
Then you just have to refer to the pointer to get the data. After all,
there's more than one way to skin your cat.
ie:

Code:

cls
dim a$(1:10), b$(1:10), c$(1:10), d$(1:10)
dim atag%(1:10)
FOR i% = 1 TO 10
  a$(i%) = CHR$(42+i%)
  b$(i%) = CHR$(42+i%)
  c$(i%) = CHR$(42+i%)
  d$(i%) = CHR$(42+i%)
  atag%(i%) = i%
NEXT i%
ARRAY SORT a$(), TAGARRAY atag%(), DESCEND
FOR i% = 1 to 10
  PRINT aTag%(i%); a$(i%); " "; b$(aTag%(i%)); " "; d$(aTag%(i%))
NEXT i%

Regards, Ian Cairns

**Lance Edmonds** · 14 Dec 1999, 03:32 AM

Using a sorted index approach is certainly the most efficient, but lets say you still want to sort more than two arrays. It can be accomplished in a few different ways:
1. Use a discrete dsorting algorythm. Search the internet for "sort algorythm" and you'll probably find hundreds of examples.
2. Use the internal ARRAY SORT technique, but it requires the use of a pair of additional numeric arrays to help us along... one to hold the master "sorted order", and another as a "work array".

For example:
Lets say you want to sort the "key" array a$(), and then and sort b$(), c$() and d$() (which can be considered "tagarrays"). First we create a numeric array, lets say we call it x%(), and then we fill the subscripts of x%() with the subscript number, ie:

'Psuedo code
DIM x%(1:NumElements%)
For i% = 1 to NumElements%
x%(i%) = i%
Next i%

Now we sort the key array, and use x%() as the tagarray, ie:

'psuedo code
ARRAY SORT a$(1) for NumElements%, COLLATE UCASE, TAGARRAY x%()

At this point, x%() contains the "sorted order" of the a$() array. We can think of x%() containing the "master sort order". Now in order to sort the additional "tagarrays", we duplicate the master sort order array and perform a sort operation on it. The trick is to use one of the additional tagarrays as a tagarrays to this sort operation! (confusing, huh!)

'PSUEDO CODE
DIM y%(1:NumELements%)
FOR i% = 1 to NumELements%
y%(i%) = x%(i)
NEXT i%
ARRAY SORT y%(1) FOR NumElements%, TAGARRAY b$()

At this point, we have sorted a$(), and b$() has been sorted as a tagarray. x%() continues holds the master "sorted order", so to sort yet another array, we copy the x%() array into the y%() array again, and sort the Y%() array with a tagarray again.

'PSUEDO CODE
DIM y%(1:NumELements%)
FOR i% = 1 to NumELements%
y%(i%) = x%(i)
NEXT i%
ARRAY SORT y%(1) FOR NumElements%, TAGARRAY c$()
'PSUEDO CODE
DIM y%(1:NumELements%)
FOR i% = 1 to NumELements%
y%(i%) = x%(i)
NEXT i%
ARRAY SORT y%(1) FOR NumElements%, TAGARRAY d$()

Finally, we can erase our additional arrays, ie,
ERASE x%(), y%()

If we only wanted to sort one tagarray, we could use the x%() array directly, but that would be inefficient as ARRAY SORT can sort one additional tagarray directly

Clear as mud?

-------------
Lance
PowerBASIC Support
( mailto:[email protected][email protected]</A> )

**Michael Mattias** · 14 Dec 1999, 04:04 AM

"I want to sort a$() and tag along b$() c$() and d$()
What is the best way to do this since the TAGARRAY
only works with one array."

Either use the index pointer approach earlier, OR:

Make the array to be sorted a UDT array like:
TYPE ControlType
KeyValue AS STRING * 12 ' what was in A$(), to be sorted
ElementNo AS INTEGER ' element number for a, b, c and d'
END TYPE

Then, sort the array using FROM ..TO...

DIM AArray(size) AS ControlType
...
ARRAY SORT AArray ,FROM 1 to 12 (no Tagarray needed)

Now your sorted array contains the element numbers for B(), C() and D() corresponding to the sorted A().

-------------
Michael Mattias
Racine WI USA
[email protected]

**David H Fisher Jr** · 14 Dec 1999, 04:11 PM

Thanks to everyone for your help!

**David H Fisher Jr** · 9 Jan 2000, 07:11 AM

I have tried to use Lance Edmonds' ideas in his reply but I can't get it to work. Here are the specifics:

DIM playername$(29)
DIM playergame(29)
DIM defenserebounds(29)
DIM average(29)

The arrays are filled from 0 to 12 (total of 13 players)

I want to print out the defensive rebounds from the highest average to the lowest average.

First I want to sort by games in descending order as if players have the same average, I want the player with the most games to be ahead of a player with fewer games

Next I want to sort by the total rebounds as I want the player with the most rebounds ahead of a player with the same average but with fewer rebounds.

Finally I want to sort by the average with the highest average first.

How do I do this. A specific example would be very helpful.

Thanks as I have been struggling with this for almoat a month!!

Dave

**Tim Wisseman** · 9 Jan 2000, 11:49 AM

Here is how to do it.

Code:

DIM playername(0 TO 29) AS String
DIM playergame(0 TO 29) AS Long
DIM defenserebounds(0 TO 29) AS Long
DIM average(0 TO 29)AS Long

DIM ptIndex(0 TO 29) AS LONG
DIM v(0 TO 29) AS Long
Dim vT As Long
Dim ptT As Long
Dim sA As String

DIM i AS LONG
Dim fg as Long

   '// Test data //
   Randomize Timer
   For i = 0 to 29
      playergame(i) = Int(rnd * 200)
      playername(i) = "Player " + Chr$(65 + i)
      defenserebounds(i) = Int(Rnd * 300)
      average(i) = Int(rnd * 399)
   Next i

   '  First I want to sort by games in descending order
   ' and if players have the same average, I want the player
   ' with the most games to be ahead of a player with fewer games
   '// Set starting sort values //
   FOR i = 0 TO 29
      ptIndex(i) = i
      v(i) = defenserebounds(i)
   NEXT i
   '// Sort    v(0) will hold the highest value
   fg = 1
   Do While fg = 1
      fg = 0
      FOR i = 28 To 0 Step -1
         IF v(i) < v(i + 1) THEN
            fg = 1
            '// Swap i with i + 1 //
            vT = v(i)
            ptT = ptIndex(i)
            v(i) = v(i + 1)
            ptIndex(i) = ptIndex(i + 1)
            v(i + 1) = vT
            ptIndex(i + 1) = ptT
         End If
         If v(i) = v(i + 1) Then
            If playergame(ptIndex(i)) < playergame(ptIndex(i + 1)) Then
               fg = 1
               '// Swap i with i + 1 //
               vT = v(i)
               ptT = ptIndex(i)
               v(i) = v(i + 1)
               ptIndex(i) = ptIndex(i + 1)
               v(i + 1) = vT
               ptIndex(i + 1) = ptT
            End If
         End If
      Next i
   Loop

   cls
   print "Defense Rebounds List 1"
   GoSub PrintPlayers

   'Next I want to sort by the total rebounds
   FOR i = 0 TO 29
      ptIndex(i) = i
      v(i) = defenserebounds(i)
   NEXT i
   '// Sort    v(0) will hold the highest value
   fg = 1
   Do While fg = 1
      fg = 0
      FOR i = 28 To 0 Step -1
         IF v(i) < v(i + 1) THEN
            fg = 1
            '// Swap i with i + 1 //
            vT = v(i)
            ptT = ptIndex(i)
            v(i) = v(i + 1)
            ptIndex(i) = ptIndex(i + 1)
            v(i + 1) = vT
            ptIndex(i + 1) = ptT
         End If
      Next i
   Loop

   cls
   print "Defense Rebounds List 2"
   GoSub PrintPlayers

   'Finally I want to sort by the average with the highest average first.
   FOR i = 0 TO 29
      ptIndex(i) = i
      v(i) = average(i)
   NEXT i
   '// Sort    v(0) will hold the highest value
   fg = 1
   Do While fg = 1
      fg = 0
      FOR i = 28 TO 0 Step - 1
         IF v(i) < v(i + 1) THEN
            fg = 1
            '// Swap i with i + 1 //
            vT = v(i)
            ptT = ptIndex(i)
            v(i) = v(i + 1)
            ptIndex(i) = ptIndex(i + 1)
            v(i + 1) = vT
            ptIndex(i + 1) = ptT
         End If
      Next i
   loop

   cls
   print "Averages"
   GoSub PrintPlayers


   End

PrintPlayers:
   For i = 0 to 29
      sA = playername(ptIndex(i)) + "  "
      sA = sA + Str$(playergame(ptIndex(i))) + "  "
      sA = sA + Str$(defenserebounds(ptIndex(i))) + "  "
      sA = sA + Str$(average(ptIndex(i))) + "  "
      print sA
      If i = 15 Then
         do while inkey$ = ""
         loop
      end if
   Next i

   do while inkey$ = ""
   loop

Return

Tim Wisseman
[email protected]

**David H Fisher Jr** · 11 Jan 2000, 05:42 PM

Thanks for Tim Wisseman's help. Unfortunately I am still a fairly new programmer in Power Basic and was not familiar with some of his commands etc. I have now been able to use Lance Edmonds' ARRAY SORT with the TAGARRAY. However I don't understand how some of the sorts work. Here is one example:

DIM playername$(20)
DIM playergame(29)
DIM defenserd(20)
DIM average(29)

Here is the order before the first sort by games:

Player Gm Drbs Avg
McDonnell,B 4 6 1.50
Gillory,T 4 10 2.50
Ramirez,Ian 4 8 2.00
Robinson,T 4 11 2.75
Bates,Aaron 4 6 1.50
Carter,T 4 6 1.50
Johnson,O 4 5 1.25
Gilchrist,D 4 9 2.25
Cunningham,E 3 2 0.67
Triplett,D 3 1 0.33
Conklin,B 1 0 0.00
Turner,Micah 2 0 0.00
Boyd,Chris 1 0 0.00

Here is the order after I sort by games:

Player Gm Drbs Avg
McDonnell,B 4 6 1.50
Gillory,T 4 10 2.50
Ramirez,Ian 4 8 2.00
Robinson,T 4 11 2.75
Bates,Aaron 4 6 1.50
Carter,T 4 6 1.50
Johnson,O 4 5 1.25
Gilchrist,D 4 9 2.25
Cunningham,E 3 2 0.67
Triplett,D 3 1 0.33
Turner,Micah 2 0 0.00
Conklin,B 1 0 0.00
Boyd,Chris 1 0 0.00

Next I sort by Rebounds:

Player Gm Drbs Avg

Robinson,T 4 11 2.75
Gillory,T 4 10 2.50
Gilchrist,D 4 9 2.25
Ramirez,Ian 4 8 2.00
McDonnell,B 4 6 1.50
Carter,T 4 6 1.50 ? Why were they switched?
Bates,Aaron 4 6 1.50 ?
Johnson,O 4 5 1.25
Cunningham,E 3 2 0.67
Triplett,D 3 1 0.33
turner,Micah 2 0 0.00
Conklin,B 1 0 0.00
Boyd,Chris 1 0 0.00

Finally I sort by average:

Player Gm Drbs Avg
Robinson,T 4 11 2.75
Gillory,T 4 10 2.50
Gilchrist,D 4 9 2.25
Ramirez,Ian 4 8 2.00
McDonnell,B 4 6 1.50
Carter,T 4 6 1.50
Bates,Aaron 4 6 1.50
Johnson,O 4 5 1.25
Cunningham,E 3 2 0.67
Triplett,D 3 1 0.33
Turner,Micah 2 0 0.00
Conklin,B 1 0 0.00
Boyd,Chris 1 0 0.00

Why was Carter moved ahead of Bates after being sorted by rebounds?

Again I used Lance Edmonds' ARRAY SORT with the TAGARRAY

Thanks,

Dave

**Lance Edmonds** · 11 Jan 2000, 07:59 PM

ARRAY SORT uses a proprietary "quick sort" algorythm, which means that ARRAY SORT
sorts without regard to existing positions in an array. In other words, it sorts
on the absolute value of the subscripts, exactly as you found.

This works fine for many situations, but in your case, you are really looking
to perform a sort based on two keys: "rebounds" and "names". Therefore this
requires a slightly different aproach... there are a couple of techniques to
consider:

1. Sort the array first by "rebounds", then examine the results and perform
another sort on the "names" limited to the range of elements where the "rebounds"
values are identical. The would ensure that where the rebounds values are identical,
the names in that range are sorted in alphanumeric order. ARRAY SORT provides methods
of limiting the range of subscripts that are sorted.

2. build a new key array that comprises both rebounds and names to form a single key.
This technique means that a single sort can be used in place of the dual sort method
in #1 above. For example, the new key could be made in the following format:
"#####.## <---name--->". Creating a key like this is a cinch with the USING$() function.
Additionally, this technique allows you to continue with the multiple array sorting
techniques discussed earlier in this thread.

-------------
Lance
PowerBASIC Support
( mailto:[email protected][email protected]</A> )

**Michael Mattias** · 12 Jan 2000, 04:50 AM

So, you want to do some multiple-key sorting?

Here are two articles from "BASICally Speaking" you should pick up:

"Mukti-Key Sorting" by Alan Earnshaw, June 1995
"Multi-Key Sorting Revisited" by Michael Mattias, May 1997

Reprints are four US bucks each. You can order at the publisher's web site: http://www.infoms.com

-------------
Michael Mattias
Racine WI USA
[email protected]

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