public static DictionaryOfLists <K, V> ToDictionaryOfLists <K, V>(this IEnumerable <V> self, Func <V, K> keySelector) { var r = new DictionaryOfLists <K, V>(); foreach (var x in self) { r.Add(keySelector(x), x); } return(r); }
public static (List <(TKey key, List <TValue> values)> shared, List <(TKey key, TValue value)> unique) SplitByCount <TKey, TValue>(this DictionaryOfLists <TKey, TValue> items) {