def clear_header_cols
      clear_header = @header_cols.select { |col| col !~ /^\(?c\d+[=~+]{,2}/ }
      if @sort
        clear_header.slice!(0, @sort.to_i) + clear_header.sort
      else
        clear_header
      end
    end
def clear_header_cols
      clear_header = @header_cols.select { |col| col !~ /^\(?c\d+[=~+]{,2}/ }
      if @sort
        clear_header.slice!(0, @sort.to_i) + clear_header.sort
      else
        clear_header
      end
    end
Returns @header_cols without pattern. Will be sorted if sorted is not nil