add method

@override void add(String element)

Adds element to this column.

Implementation

@override
void add(String element) {
  _statsCache.clear();
  if (element.toUpperCase() == missingValueMarker) {
    _data.add(-1);
  } else {
    if (!_categories.contains(element)) {
      _categories.add(element);
    }
    _data.add(_categories.indexOf(element));
  }
}