没文化 用惯了正则 没能完成hash查找 虽然还是不知道他们是否有什么关联

unit Main;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes,
  Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ComCtrls;

type
  TForm1 = class(TForm)
    btn1: TButton;
    dlgOpen1: TOpenDialog;
    lv1: TListView;
    procedure btn1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}
uses
  System.RegularExpressions;

var
  ss: TStringStream;

procedure TForm1.btn1Click(Sender: TObject);
var
  I: Integer;
  item: TListItem;
  temp: string;
  zimu: string;
  matchs: TMatchCollection;
begin
  with dlgOpen1 do
  begin
    Filter := ‘文本文件(*.txt)|*.txt‘;
    DefaultExt := ‘txt‘;
    FileName := ‘‘;
    Options := [ofHideReadOnly, ofEnableSizing];
    if dlgOpen1.Execute then
      if ofExtensionDifferent in Options then
        messagedlg(‘这不是文本文件‘, mterror, [mbok], 0)
      else
        ss.LoadFromFile(FileName);
    temp := LowerCase(ss.DataString);
  end;
  lv1.Clear;
  for I := 0 to 26 do
  begin
    zimu := AnsiChar(97 + I);
    item := lv1.Items.Add;
    item.Caption := zimu;
    matchs := TRegEx.Matches(temp, zimu);
    item.SubItems.Add(IntToStr(matchs.Count));
  end;
  item.Free;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  ss := TStringStream.Create;
end;

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

end.