需要引用单元 System.regularexpressionscore
procedure TForm1.Button2Click(Sender: TObject);
Var
  Reg: TPerlRegEx;
  S: String;
begin
  S := 'abc123456';
  Reg := TPerlRegEx.Create;
  Reg.Subject := S;
  Reg.RegEx := 'abc(\d+)';
  while Reg.MatchAgain do
  Begin
    Memo1.Lines.Add(Reg.Groups[1]);
  End;
end;