// Полный аналитический сценарий
uses DataFrameABC;

begin
  var df := DataFrame.FromCsvText('''
  name,age,score
  Alice,20,85
  Bob,22,90
  Charlie,21,78
  Bob,22,90
  Clara,,78
  Kat,21,NA
  ''');
  
  df
  .Filter(r -> r.IsValid('score'))
  .SortBy('age', descending := True)
  .GroupBy('age')
  .Mean('score')
  .Print;
end.