• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 1716
  • Last Modified:

Delphi What is the best way to sort an Array of String

What is the fastest sort to alphabetically sort an Array of String.  The arrays will generally be smalish, about 20 elements.  I am using Delphi 2010 and beleve there is a built in function to do this, if so what is the function and how is it used?
0
HenryM2
Asked:
HenryM2
  • 4
  • 3
1 Solution
 
aflarinCommented:
You're right. There is a built in function for array of string. But not for dynamic array. It is for TStrings class:

var
  StrArray: TStrings;
begin
  StrArray:= TStringList.Create;
  try
    StrArray.Add( 'Str 1' );
    StrArray.Add( 'Str 2' );
    StrArray.Add( 'Str 3' );
    StrArray.Sort; <------------------------
  finally
    StrArray.Free;
  end;


0
 
aflarinCommented:
If you are using D2010, try something like this

TArray.Sort<string>(YourArray , TDelegatedComparer<string>.Construct(
  function(const Left, Right: string): Integer
  begin
    Result := TComparer<String>.Default.Compare(Left, Right);
  end));
0
 
aflarinCommented:
Here is tested example:

uses
  Generics.Defaults,
  Generics.Collections;

procedure TForm1.Button1Click(Sender: TObject);
var
  StrArray: array of string;
begin
  SetLength( StrArray, 3);
  StrArray[0]:= 'Str 3';
  StrArray[1]:= 'Str 2';
  StrArray[2]:= 'Str 1';

  TArray.Sort<string>(StrArray , TDelegatedComparer<string>.Construct(
    function(const Left, Right: string): Integer
    begin
      Result := TComparer<String>.Default.Compare(Left, Right);
    end));
end;
0
Concerto's Cloud Advisory Services

Want to avoid the missteps to gaining all the benefits of the cloud? Learn more about the different assessment options from our Cloud Advisory team.

 
aflarinCommented:
Even shorter:

uses
  Generics.Defaults,
  Generics.Collections;

procedure TForm1.Button1Click(Sender: TObject);
var
  StrArray: array of string;
begin
  SetLength( StrArray, 3);
  StrArray[0]:= 'Str 3';
  StrArray[1]:= 'Str 2';
  StrArray[2]:= 'Str 1';

  TArray.Sort<string>(StrArray); // <----------------
end;
0
 
HenryM2Author Commented:
I am having difficulty to get it working.  I have not used TStrings before, is there a Unit to be listes in Uses for this. I added the Uses caluses that you used but get Incompatible type error in line "SetLength( StrArray, 3);"

I also get [DCC Error] SiteDesignerMainUnt.pas(9710): E2250 There is no overloaded version of 'TArray.Sort<System.string>' that can be called with these arguments for line " TArray.Sort<string>(StrArray);"
0
 
HenryM2Author Commented:
Sorry, my previous commnet = false alarm, now working.
0
 
HenryM2Author Commented:
Thanks, works great.
0

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

  • 4
  • 3
Tackle projects and never again get stuck behind a technical roadblock.
Join Now