[SOLVED] Help with TFPGMAP sort...

[Espectr0]

Hello,
I have problems to order a TFPGMAP according to the DATA value:

type:

Code: Pascal  [Select][+][-]

1. TTMXList = specialize TFPGMap<Integer, Double>;

data compare:

Code: Pascal  [Select][+][-]

1. function DataCompare(const Data1, Data2: Double): Integer;
2. begin
3.   if Data1 < Data2 then
4.     Result := -1
5.   else if Data1 > Data2 then
6.     Result := 1
7.   else
8.     Result := 0;
9. end;            

Try the 'Sorted := True' property and 'Sort' but I can't get it to order.

What am I doing wrong?
thanks

[bytebites]

...
What am I doing wrong?

You provided only code snippets.

Code: Pascal  [Select][+][-]

1. program Project1;
2. {$mode delphi}
3. uses fgl;
4. type
5.   tmap=tfpgmap<integer,double>;
6. var
7.   m:tmap;
8.   i: Integer;
9. begin
10.   m:=tmap.create;
11.   m.Sorted:=true;
12.   m.Add(1,1.1);
13.   m.Add(8,4.2);
14.   m.Add(2,2.3);
15.   m.Add(0,0.4);
16.   for i:=0 to m.Count-1 do writeln(m.Data[i]:4:1);
17. end.      
18.  

Output is
 0.4
 1.1
 2.3
 4.2

[JdeHaan]

I believe sorting is done on the key only if you set sorted to true...

[Espectr0]

Thanks @bytebites but @JdeHaan is right, the sort is based on the "KEY", so I tried "OnDataCompare" but I can't get it to work that way, any ideas?

[Warfley]

Maps can only sort on the key, they are simply not designed to sort for data. Either use another datastructure or sort the data yourself.

I use this opportunity to plug my iterator library, which allows this:

Code: Pascal  [Select][+][-]

1. program Project1;
2.  
3. {$mode Delphi}
4. {$ModeSwitch implicitfunctionspecialization}
5.  
6. uses
7.   Generics.Collections, iterators;
8.  
9. type
10.   TIntDoubleMap = TDictionary<Integer, Double>;
11.   TIntDoublePair = TPair<Integer, Double>;
12.  
13. function ComparePairValue(A, B: TIntDoublePair): Boolean;
14. begin
15.   Result := A.Value < B.Value;
16. end;
17.  
18. var
19.   data: TIntDoubleMap;
20.   p: TIntDoublePair;
21. begin
22.   data := TIntDoubleMap.Create;
23.   try
24.     data.Add(1, 5);
25.     data.Add(2, 3);
26.     data.Add(4, 6);
27.     data.Add(10, 1);
28.     for p in Sorted(Iterate(data), ComparePairValue) do
29.       WriteLn(p.Value);
30.   finally
31.     data.Free;
32.   end;
33.   ReadLn;
34. end.
35.  

[Espectr0]

Thanks @Warfley, I'm going to investigate your library, I find it very interesting. Regards!