泛型排序

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unit Unit1;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, StdCtrls;type  TForm1 = class(TForm)    Memo1: TMemo;    Memo2: TMemo;    Button1: TButton;    Button2: TButton;    Button3: TButton;    Button4: TButton;    Button5: TButton;    Button6: TButton;    Button7: TButton;    Button8: TButton;    Button9: TButton;    Button10: TButton;    procedure Button1Click(Sender: TObject);    procedure Button2Click(Sender: TObject);    procedure Button3Click(Sender: TObject);    procedure Button4Click(Sender: TObject);    procedure Button5Click(Sender: TObject);    procedure Button6Click(Sender: TObject);    procedure Button7Click(Sender: TObject);    procedure Button8Click(Sender: TObject);    procedure Button9Click(Sender: TObject);    procedure Button10Click(Sender: TObject);  end;var  Form1: TForm1;implementation{$R *.dfm}uses Generics.Collections, Generics.Defaults; {必需的泛型单元}//构建由 10 个整数组成的动态数组, 然后排序procedure TForm1.Button1Click(Sender: TObject);var  arr: array of Integer;  i: Integer;begin  {构建动态数组}  Randomize;  for i := 0 to 9 do begin    SetLength(arr, Length(arr)+1);    arr[i] := Random(10);  end;  {显示排序前}  Memo1.Clear;  for i := 0 to Length(arr) - 1 do Memo1.Lines.Add(IntToStr(arr[i]));  {排序}  TArray.Sort<Integer>(arr); {它可以有 1个、2个、4个参数, 这里只用了一个参数, 其他是默认参数}  {显示排序结果}  Memo2.Clear;  for i := 0 to Length(arr) - 1 do Memo2.Lines.Add(IntToStr(arr[i]));end;// TArray.Sort 的第二个参数是 IComparer<T> 类型, 其默认值是: TComparer<T>.Defaultprocedure TForm1.Button2Click(Sender: TObject);var  arr: array of Integer;  i: Integer;begin  Randomize;  for i := 0 to 9 do begin    SetLength(arr, Length(arr)+1);    arr[i] := Random(10);  end;  Memo1.Clear;  for i := 0 to Length(arr) - 1 do Memo1.Lines.Add(IntToStr(arr[i]));  {使用了排序器的默认值排序, 这和忽略这个参数是一样的}  TArray.Sort<Integer>(arr, TComparer<Integer>.Default);  Memo2.Clear;  for i := 0 to Length(arr) - 1 do Memo2.Lines.Add(IntToStr(arr[i]));end;//同上两例, 变通了一下写法procedure TForm1.Button3Click(Sender: TObject);var  arr: array of Integer;  i: Integer;  Comparer: IComparer<Integer>;begin  Randomize;  for i := 0 to 9 do begin    SetLength(arr, Length(arr)+1);    arr[i] := Random(10);  end;  Memo1.Clear;  for i := 0 to Length(arr) - 1 do Memo1.Lines.Add(IntToStr(arr[i]));  Comparer := TComparer<Integer>.Default;  TArray.Sort<Integer>(arr, Comparer);  Memo2.Clear;  for i := 0 to Length(arr) - 1 do Memo2.Lines.Add(IntToStr(arr[i]));end;// TArray.Sort 的后面两个参数可以指定排序范围:procedure TForm1.Button4Click(Sender: TObject);var  arr: array of Integer;  i: Integer;  Comparer: IComparer<Integer>;begin  Randomize;  for i := 0 to 9 do begin    SetLength(arr, Length(arr)+1);    arr[i] := Random(10);  end;  Memo1.Clear;  for i := 0 to Length(arr) - 1 do Memo1.Lines.Add(IntToStr(arr[i]));  Comparer := TComparer<Integer>.Default;  {这里指定从第 1 个元素开始, 只给 3 个元素排序}  TArray.Sort<Integer>(arr, Comparer, 0, 3);  Memo2.Clear;  for i := 0 to Length(arr) - 1 do Memo2.Lines.Add(IntToStr(arr[i]));end;//如果要倒排序, 可以建立自己的排序器, 下面就是先构建并实现了一个 TMyComparer, 然后调用:type  TMyComparer = class(TComparer<Integer>)  public    function Compare(const Left, Right: Integer): Integer; override;  end;{ TMyComparer }function TMyComparer.Compare(const Left, Right: Integer): Integer;begin  Result := Right - Left;end;procedure TForm1.Button5Click(Sender: TObject);var  arr: array of Integer;  i: Integer;  Comparer: TMyComparer;begin  Randomize;  for i := 0 to 9 do begin    SetLength(arr, Length(arr)+1);    arr[i] := Random(10);  end;  Memo1.Clear;  for i := 0 to Length(arr) - 1 do Memo1.Lines.Add(IntToStr(arr[i]));  Comparer := TMyComparer.Create;  TArray.Sort<Integer>(arr, Comparer);  Memo2.Clear;  for i := 0 to Length(arr) - 1 do Memo2.Lines.Add(IntToStr(arr[i]));  Comparer.Free;end;// 也可以用 TComparer<T>.Construct 方法, 通过一个 TComparison 格式的函数构建排序器, 这样简单一些function MyFunc1(const Left, Right: Integer): Integer;begin  Result := Right - Left;end;procedure TForm1.Button6Click(Sender: TObject);var  arr: array of Integer;  i: Integer;  Comparer: IComparer<Integer>;begin  Randomize;  for i := 0 to 9 do begin    SetLength(arr, Length(arr)+1);    arr[i] := Random(10);  end;  Memo1.Clear;  for i := 0 to Length(arr) - 1 do Memo1.Lines.Add(IntToStr(arr[i]));  Comparer := TComparer<Integer>.Construct(MyFunc1);  TArray.Sort<Integer>(arr, Comparer);  Memo2.Clear;  for i := 0 to Length(arr) - 1 do Memo2.Lines.Add(IntToStr(arr[i]));end;//如果是给自定义类型的元素排序, 只能是自建排序器type  TPerson = record    name: string;    age: Word;  end;function MyFunc2(const Left, Right: TPerson): Integer;begin  Result := Left.age - Right.age;end;procedure TForm1.Button7Click(Sender: TObject);var  arr: array of TPerson;  i: Integer;  Comparer: IComparer<TPerson>;begin  SetLength(arr, 4);  arr[0].name := 'AA'; arr[0].age := 22;  arr[1].name := 'BB'; arr[1].age := 33;  arr[2].name := 'CC'; arr[2].age := 44;  arr[3].name := 'DD'; arr[3].age := 11;  Memo1.Clear;  for i := 0 to Length(arr) - 1 do    Memo1.Lines.Add(Format('%s : %d', [arr[i].name, arr[i].age]));  Comparer := TComparer<TPerson>.Construct(MyFunc2);  TArray.Sort<TPerson>(arr, Comparer);  Memo2.Clear;  for i := 0 to Length(arr) - 1 do    Memo2.Lines.Add(Format('%s : %d', [arr[i].name, arr[i].age]));end;// TStringComparer.Ordinal 是官方实现的用于 string 的排序器, 可直接使用.//但它好像有问题(Delphi 2010 - 14.0.3513.24210), 以后的版本应该能改过来.procedure TForm1.Button8Click(Sender: TObject);var  arr: array of string;  i: Integer;begin  SetLength(arr, 4);  arr[0] := '222';  arr[1] := '111';  arr[2] := 'bbb';  arr[3] := 'aaa';  Memo1.Clear;  for i := 0 to Length(arr) - 1 do Memo1.Lines.Add(arr[i]);  TArray.Sort<string>(arr, TStringComparer.Ordinal);  Memo2.Clear;  for i := 0 to Length(arr) - 1 do Memo2.Lines.Add(arr[i]);end;//下面是实现字符串数组的到排序function MyComparerFunc(const s1,s2: string): Integer;begin  Result := CompareText(s2, s1);  //Result := -CompareText(s1, s2); {或者这样}end;procedure TForm1.Button9Click(Sender: TObject);var  arr: array of string;  i: Integer;  Comparer: IComparer<string>;begin  Memo1.Clear;  Memo1.Lines.CommaText := '11,33,22,AAA,CCC,BBB';  SetLength(arr, Memo1.Lines.Count);  for i := 0 to Length(arr) - 1 do arr[i] := Memo1.Lines[i];  Comparer := TComparer<string>.Construct(MyComparerFunc);  TArray.Sort<string>(arr, Comparer);  Memo2.Clear;  for i := 0 to Length(arr) - 1 do Memo2.Lines.Add(arr[i]);end;//可以把上一个程序简写为:procedure TForm1.Button10Click(Sender: TObject);var  arr: array of string;  i: Integer;  Comparer: IComparer<string>;begin  Memo1.Clear;  Memo1.Lines.CommaText := '11,33,22,AAA,CCC,BBB';  SetLength(arr, Memo1.Lines.Count);  for i := 0 to Length(arr) - 1 do arr[i] := Memo1.Lines[i];  Comparer := TComparer<string>.Construct(    function (const s1,s2: string): Integer    begin      Result := CompareText(s2, s1);    end);  TArray.Sort<string>(arr, Comparer);  Memo2.Clear;  for i := 0 to Length(arr) - 1 do Memo2.Lines.Add(arr[i]);end;end.

测试窗体文件(之所以附上窗体文件, 是为了再次测试方便):

object Form1: TForm1  Left = 0  Top = 0  Caption = 'Form1'  ClientHeight = 321  ClientWidth = 318  Color = clBtnFace  Font.Charset = DEFAULT_CHARSET  Font.Color = clWindowText  Font.Height = -11  Font.Name = 'Tahoma'  Font.Style = []  OldCreateOrder = False  PixelsPerInch = 96  TextHeight = 13  object Memo1: TMemo    Left = 0    Top = 0    Width = 89    Height = 321    Align = alLeft    Lines.Strings = (      'Memo1')    TabOrder = 0    ExplicitHeight = 299  end  object Button1: TButton    Left = 120    Top = 8    Width = 75    Height = 25    Caption = 'Button1'    TabOrder = 1    OnClick = Button1Click  end  object Button2: TButton    Left = 120    Top = 39    Width = 75    Height = 25    Caption = 'Button2'    TabOrder = 2    OnClick = Button2Click  end  object Button3: TButton    Left = 120    Top = 70    Width = 75    Height = 25    Caption = 'Button3'    TabOrder = 3    OnClick = Button3Click  end  object Memo2: TMemo    Left = 219    Top = 0    Width = 99    Height = 321    Align = alRight    Lines.Strings = (      'Memo2')    TabOrder = 4    ExplicitHeight = 299  end  object Button4: TButton    Left = 120    Top = 101    Width = 75    Height = 25    Caption = 'Button4'    TabOrder = 5    OnClick = Button4Click  end  object Button5: TButton    Left = 120    Top = 132    Width = 75    Height = 25    Caption = 'Button5'    TabOrder = 6    OnClick = Button5Click  end  object Button6: TButton    Left = 120    Top = 163    Width = 75    Height = 25    Caption = 'Button6'    TabOrder = 7    OnClick = Button6Click  end  object Button7: TButton    Left = 120    Top = 194    Width = 75    Height = 25    Caption = 'Button7'    TabOrder = 8    OnClick = Button7Click  end  object Button8: TButton    Left = 120    Top = 225    Width = 75    Height = 25    Caption = 'Button8'    TabOrder = 9    OnClick = Button8Click  end  object Button9: TButton    Left = 120    Top = 256    Width = 75    Height = 25    Caption = 'Button9'    TabOrder = 10    OnClick = Button9Click  end  object Button10: TButton    Left = 120    Top = 287    Width = 75    Height = 25    Caption = 'Button10'    TabOrder = 11    OnClick = Button10Click  endend

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