createForJoin<TKey, TValue> method
- Iterable<
TValue> source, - TKey keySelector(
- TValue
- EqualityComparer<
TKey> comparer
Implementation
static Lookup<TKey, TValue> createForJoin<TKey, TValue>(
Iterable<TValue> source,
TKey Function(TValue) keySelector,
EqualityComparer<TKey> comparer,
) {
ArgumentError.checkNotNull(source);
ArgumentError.checkNotNull(keySelector);
final lookup = Lookup<TKey, TValue>._internal(comparer);
for (final item in source) {
final key = keySelector(item);
if (key != null) lookup.getGrouping(key, true).add(item);
}
return lookup;
}