operator [] method
The object at the given index
in the list.
The index
must be a valid index of this list,
which means that index
must be non-negative and
less than length.
Implementation
@override
E operator [](int index) {
for (int i = 0; i < _lists.length; i++) {
List<E> list = _lists[i];
if (index < list.length) return list[index];
index -= list.length;
}
throw StateError('Index out of range: $index ($length)');
}