How can I search faster for name/value pairs in a Delphi TStringList?

LaBracca picture LaBracca · Sep 14, 2010 · Viewed 14.8k times · Source

I implemented language translation in an application by putting all strings at runtime in a TStringList with:

procedure PopulateStringList;
begin  
  EnglishStringList.Append('CAN_T_FIND_FILE=It is not possible to find the file');
  EnglishStringList.Append('DUMMY=Just a dummy record');
  // total of 2000 record appended in the same way
  EnglishStringList.Sorted := True; // Updated comment: this is USELESS!
end;

Then I get the translation using:

function GetTranslation(ResStr:String):String;
var
  iIndex : Integer;
begin
  iIndex := -1;
  iIndex :=  EnglishStringList.IndexOfName(ResStr);
  if iIndex >= 0 then
  Result :=  EnglishStringList.ValueFromIndex[iIndex] else
  Result := ResStr + ' (Translation N/A)';
end;

Anyway with this approach it takes about 30 microseconds to locate a record, is there a better way to achieve the same result?

UPDATE: For future reference I write here the new implementation that uses TDictionary as suggested (works with Delphi 2009 and newer):

procedure PopulateStringList;
begin  
  EnglishDictionary := TDictionary<String, String>.Create;
  EnglishDictionary.Add('CAN_T_FIND_FILE','It is not possible to find the file');
  EnglishDictionary.Add('DUMMY','Just a dummy record');
  // total of 2000 record appended in the same way
end;


function GetTranslation(ResStr:String):String;
var
  ValueFound: Boolean;
begin
  ValueFound:=  EnglishDictionary.TryGetValue(ResStr, Result);
  if not ValueFound then Result := Result + '(Trans N/A)';
end;

The new GetTranslation function performs 1000 times faster (on my 2000 sample records) then the first version.

Answer

splash picture splash · Sep 14, 2010

THashedStringList should be better, I think.