code: public TColumn getColumnByIndex(int index) {
          if (columns == null) {
              return null;
          }
  
          TColumn result = null;
          for (TColumn column : columns) {
              if (column.getIndex() == index) {
                  result = column;
                  break;
              }
          }
          return result;
      }
docs: Get a column by index.
  
  @param index the column index
  @return the column by index