resetCategories method
Resets the categories; for example, if we would like the categories of two categoric columns to match.
Implementation
void resetCategories(Iterable<String> categories) {
final newCategories = [
...{
for (final c in categories)
if (c.toUpperCase() != missingValueMarker) c
}
];
for (var i = 0; i < length; i++) {
final value = this[i];
_data[i] =
value == missingValueMarker ? -1 : newCategories.indexOf(value);
}
this._categories
..clear()
..addAll(categories);
}