详测 Generics Collections TList (9): BinarySearch

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses Generics.Collections, Generics.Defaults;

procedure TForm1.Button1Click(Sender: TObject);
var
  List: TList<string>;
  num: Integer;
  b: Boolean;
  Comparer: IComparer;
begin
  List := TList<string>.Create();
  List.AddRange(['123', 'ABB', 'ABC']);

  {默认的查找需要完全吻合才能找到}
  if List.BinarySearch('ABC', num) then ShowMessage(IntToStr(num)); {2}

  {这里自定义个对比器, 只要第一个字符吻合就算找到了}
  Comparer := TComparer<string>.Construct(
    function(const s1,s2: string): Integer
    begin
      Result := Ord(s1[1]) - Ord(s2[1]);
    end);

  if List.BinarySearch('ABC', num, Comparer) then ShowMessage(IntToStr(num)); {1}
      
  List.Free;
end;

end.