groupByIndexedAndWhere<K> method
groupBy extension for List Grock GroupBy
Implementation
Map<K, List<E>> groupByIndexedAndWhere<K>(K Function(E value, int index) f) {
final map = <K, List<E>>{};
var i = 0;
for (final element in this) {
final key = f(element, i++);
if (key != null) {
map.putIfAbsent(key, () => <E>[]).add(element);
}
}
return map;
}