Delphi集合

集合

//定义
type
  Uppercase = 'A'..'Z';
  Letters = set of Uppercase;  //基于子界定义

  TBorderIcon = (biSystemMenu, biMinimize, biMaximize, biHelp);
  TBorderIcons = set of TBorderIcon;  //基于枚举定义

//应用
type
  Uppercase = 'A'..'Z';
  Letters = set of Uppercase;  //基于子界定义
var
  L1, L2, L3: Letters;
begin
  L1 := ['A', 'B', 'C'];
  L2 := ['K'];
  L3 := [];

  if 'A' in L1 then ShowMessage('true');  //true
  if L2=['K'] then ShowMessage('true');  //true
  if L3=[] then ShowMessage('true');  //true
end;

//判断是否属于集合
type
  TSet = set of (A,B,C);
var
  set1: TSet;
begin
  set1 := [A,B];
  if A in set1 then
    ShowMessage('集合 set1 包含 A');
end;

//集合元素的增减
type
  TSet = set of (A,B,C);
var
  set1: TSet;
begin
  set1 := [A];

  set1 := set1 + [B];  //增加一个元素
  Include(set1,B);     //增加一个元素

  set1 := set1 - [B];  //排除一个元素
  Exclude(set1,B);     //排除一个元素
end;

//集合添加元素举例
type
  TCharSet = set of char;
var
  character: 'a'..'z';
  charSet: TCharSet;
  word: string;
begin
  charSet := [];
  for character in [Low(character) .. High(character)] do
  begin
    if character in ['d', 'e', 'l', 'p', 'h', 'i'] then
    begin
      Include(charSet, character);
    end;
  end;

  for character in charSet do
  begin
    word := word + character;
  end;

  ShowMessage(word);  //dehilp
end;

获取集合元素个数

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
var
  set1: set of Char; {定义一个字符集合变量}
  c: Char;           {定义个字符用于遍历集合}
  num: Integer;      {用于计数}
begin
  set1 := ['a'..'z', 'A'..'Z', '0'..'9']; {给集合赋值}

  num := 0;
  for c in set1 do Inc(num); {遍历字符集合 set1, 让 num 计数}   

  ShowMessage(IntToStr(num)); {62}
end;

end.