transform method
Implementation
List<List<int>> transform(List<dynamic> values) {
_checkFitted();
return values.map((value) {
if (_categoryToIndex.containsKey(value)) {
final vector = List<int>.filled(_categories.length, 0);
vector[_categoryToIndex[value]!] = 1;
return vector;
} else if (handleUnknown) {
return List<int>.from(unknownVector);
} else {
throw ArgumentError('Unknown category encountered: $value');
}
}).toList();
}