Delphi 中的哈希表(1): THashedStringList

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses
  IniFiles;  //THashedStringList 来自 IniFiles 单元
var
  Hash: THashedStringList;

{ THashedStringList 继承自 TStringList, 只是覆盖了 IndexOf、IndexOfName 两个方法以增加效率;
  如果注重效率而不需要太多功能, 可以使用 TStringHash, 它是直接从 TObject 继承的数组链表 }


//建立哈希表
procedure TForm1.FormCreate(Sender: TObject);
var
  i: Integer;
begin
  Hash := THashedStringList.Create;

  for i := 97 to 122 do
  begin
    Hash.Add(Chr(i) + '=' + IntToStr(i));
  end;

  ShowMessage(Hash.Text);
{
构建结果:
  a=97
  b=98
  c=99
  d=100
  e=101
  f=102
  g=103
  h=104
  i=105
  j=106
  k=107
  l=108
  m=109
  n=110
  o=111
  p=112
  q=113
  r=114
  s=115
  t=116
  u=117
  v=118
  w=119
  x=120
  y=121
  z=122
}
end;

//检索哈希表
procedure TForm1.Button1Click(Sender: TObject);
var
  i: Integer;
begin
  i := Hash.IndexOf('z=122');
  ShowMessage(IntToStr(i));  //25

  i := Hash.IndexOfName('z');
  ShowMessage(IntToStr(i));  //25
end;

//基本操作
procedure TForm1.Button2Click(Sender: TObject);
begin
  Hash.Values['a'] := '65';       //赋值
  Hash.ValueFromIndex[0] := '65'; //用索引赋值

  ShowMessage(Hash.Values['z']);       //122, 取值
  ShowMessage(Hash.ValueFromIndex[25]);//122, 用索引取值

  {其他操作参加 TStringList}
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  Hash.Free;
end;