Sorting a string list containing numbers and strings - sorting

Question

I'm trying to sort a string grid filled with scores and strings like so:
via a sorted string list which is sorted by single columns from the grid called SUB 1, SUB 2, FINAL, TOTAL respectively (all these columns work except FINAL) and I'm not getting the results I need in the FINAL column.
I'm trying to get the column sorted like so, for example :
24
20
12
5
DNF
EXE
WE
but I'm getting this result instead (the result I do not want):
DNF
EXE
WE
24
20
12
5
In what way could I change my code to sort the grid as I want to sort it?
My code:
function Compare2(
List : TStringList;
Index1 : Integer;
Index2 : Integer) : Integer;
begin
//comparer for custom sort used in SortLTSGrid
if List[Index1] = List[Index2] then
Result := 0
else if List[Index1] < List[Index2] then
Result := 1
else
Result := -1;
end;
procedure TfrmPuntehou.SortLTSGrid(var grid: TStringGrid; columntotal: Integer);
var
TheList : TStringList;
i,l,iCount,m:integer;
const
separator = ',';
const
arrCodes:array[1..10] of string = ('DNF','DNS','WD','WE','DNA','OD','RD','EXR','EXE','PP');
begin
//sorts grid largest to smallest according to one column
//get grid row amount
iCount:=grid.RowCount - 1;
//create and fill the string list
TheList := TStringList.Create;
//fill the list
for i := 1 to (iCount) do
begin
for l := 1 to Length(arrCodes) do
begin
if grid.Rows[i].Strings[columntotal] = arrCodes[l] then
begin
TheList.Add('0'+separator+grid.Rows[i].Text);
end;
end;
TheList.Add(grid.Rows[i].Strings[columntotal]+separator+grid.Rows[i].Text);
end;
//try block to sort and write all strings in the list to the grid correctly
try
TheList.CustomSort(Compare2);
for i:= 1 to (iCount) do
begin
grid.Rows[i].Text := TheList.Strings[(i-1)] ;
end;
//fill the row numbers
for m := 1 to iCount do
begin
grid.Cells[0,m]:= IntToStr(m);
end;
finally
TheList.Free;
end;
end;

Answer 1

You can use two different lists to store items, and two different sorting functions (because you want to sort them in different direction; numbers will be ordered as decreasing and strings will be ordered as ascending) to sort lists. Sort the lists separately, and than merge them.
Please consider #David Heffernan's performance warning.
program Project3;
{$APPTYPE CONSOLE}
{$R *.res}
uses
System.SysUtils, System.Classes;
var
slStrings, slNumbers:TStringList;
test:string;
function CompareForNumbers(
List : TStringList;
Index1 : Integer;
Index2 : Integer) : Integer;
var
val1, val2:Integer;
begin
val1 := StrToInt(List[Index1]);
val2 := StrToInt(List[Index2]);
if val1 = val2 then
Result := 0
else if val1 < val2 then
Result := 1
else
Result := -1;
end;
function CompareForStrings(
List : TStringList;
Index1 : Integer;
Index2 : Integer) : Integer;
begin
if List[Index1] = List[Index2] then
Result := 0
else if List[Index1] > List[Index2] then
Result := 1
else
Result := -1;
end;
begin
slStrings := TStringList.Create();
slNumbers := TStringList.Create();
try
slStrings.Add('EXE');
slStrings.Add('WE');
slStrings.Add('DNF');
slNumbers.Add('5');
slNumbers.Add('20');
slNumbers.Add('24');
slNumbers.Add('12');
slNumbers.CustomSort(CompareForNumbers);
slStrings.CustomSort(CompareForStrings);
slNumbers.AddStrings(slStrings);
Writeln(slNumbers.Text);
Readln(test);
finally
slStrings.Free();
slNumbers.Free();
end;
end.
To use single list to handle #David Heffernan's performance warning, i've write this;
program Project3;
{$APPTYPE CONSOLE}
{$R *.res}
uses
System.SysUtils, System.Classes;
var
slStrings:TStringList;
test:string;
function Compare(
List : TStringList;
Index1 : Integer;
Index2 : Integer) : Integer;
var
val1, val2:Integer;
val1integer, val2integer:Boolean;
begin
val1integer := TryStrToInt(List[Index1], val1);
val2integer := TryStrToInt(List[Index2], val2);
if val1integer and val2integer then
begin
if val1 = val2 then
Result := 0
else if val1 < val2 then
Result := 1
else
Result := -1;
end
else if (not val1integer) And (not val2integer) then
begin
if List[Index1] = List[Index2] then
Result := 0
else if List[Index1] > List[Index2] then
Result := 1
else
Result := -1;
end
else
begin
if val1integer then
Result := -1
else
Result := 1;
end;
end;
begin
slStrings := TStringList.Create();
try
slStrings.Add('EXE');
slStrings.Add('5');
slStrings.Add('WE');
slStrings.Add('20');
slStrings.Add('DNF');
slStrings.Add('24');
slStrings.Add('12');
slStrings.Add('A');
slStrings.Add('6');
slStrings.Add('E');
slStrings.Add('B');
slStrings.Add('4');
slStrings.Add('T');
slStrings.Add('444');
slStrings.CustomSort(Compare);
Writeln(slStrings.Text);
Readln(test);
finally
slStrings.Free();
end;
end.

Answer 2

I believe you want to sort times by shortest to longest first, then all text alphabetically (although that is arguable).
I would not modify the texts in the way that you do. Instead I would simply modify the comparer function and pass the texts 'as is'.
To test it I used a TMemo, but the principle applies to the tables - just copy the appropriate column to the string list.
function Compare2(
List : TStringList;
Index1 : Integer;
Index2 : Integer) : Integer;
var
i1IsNumeric, i2IsNumeric : boolean;
i1, i2 : integer;
begin
//comparer for custom sort used in SortLTSGrid
i1IsNumeric := TryStrToInt( List[Index1], i1 );
i2IsNumeric := TryStrToInt( List[Index2], i2 );
if i1IsNumeric and (not i2IsNumeric) then
begin
Result := -1;
end
else if i2IsNumeric and (not i1IsNumeric) then
begin
Result := 1;
end
else if i1IsNumeric then
begin
Result := Sign( i1-i2);
end
else
begin
Result := CompareStr( List[Index1], List[Index2] );
end;
end;
Here is my test routine using a memo
procedure TForm4.Button1Click(Sender: TObject);
var
iList : TStringList;
begin
iList := TStringList.Create;
try
iList.Assign( Memo1.Lines );
iList.CustomSort( Compare2 );
Memo1.Lines.Assign( iList );
finally
iList.Free;
end;
end;
Your routine would be more like (although this I have not tested)
procedure TfrmPuntehou.SortLTSGrid(var grid: TStringGrid; columntotal: Integer);
var
TheList : TStringList;
i,l,iCount,m:integer;
const
separator = ',';
const
arrCodes:array[1..10] of string = ('DNF','DNS','WD','WE','DNA','OD','RD','EXR','EXE','PP');
begin
//sorts grid largest to smallest according to one column
//get grid row amount
iCount:=grid.RowCount - 1;
//create and fill the string list
TheList := TStringList.Create;
//fill the list
for i := 1 to (iCount) do
begin
TheList.Add(grid.Rows[i].Text);
end;
//try block to sort and write all strings in the list to the grid correctly
try
TheList.CustomSort(Compare2);
for i:= 1 to (iCount) do
begin
grid.Rows[i].Text := TheList.Strings[(i-1)] ;
end;
//fill the row numbers
for m := 1 to iCount do
begin
grid.Cells[0,m]:= IntToStr(m);
end;
finally
TheList.Free;
end;
end;