ToLookup< TSource, TKey, TElement >() [2/2]

static ILookup< TKey, TElement > System.Linq.ParallelEnumerable.ToLookup< TSource, TKey, TElement > ( this ParallelQuery< TSource > source, Func< TSource, TKey > keySelector, Func< TSource, TElement > elementSelector, IEqualityComparer< TKey >? comparer )

inlinestatic

Type Constraints

TKey

:

notnull

Definition at line 1880 of file ParallelEnumerable.cs.

                                                                                                                                                                                                                                        : notnull
    {
        if (source == null)
        {
            throw new ArgumentNullException("source");
        }
        if (keySelector == null)
        {
            throw new ArgumentNullException("keySelector");
        }
        if (elementSelector == null)
        {
            throw new ArgumentNullException("elementSelector");
        }
        comparer = comparer ?? EqualityComparer<TKey>.Default;
        ParallelQuery<IGrouping<TKey, TElement>> parallelQuery = source.GroupBy(keySelector, elementSelector, comparer);
        System.Linq.Parallel.Lookup<TKey, TElement> lookup = new System.Linq.Parallel.Lookup<TKey, TElement>(comparer);
        IEnumerator<IGrouping<TKey, TElement>> enumerator = ((!(parallelQuery is QueryOperator<IGrouping<TKey, TElement>> queryOperator)) ? parallelQuery.GetEnumerator() : queryOperator.GetEnumerator(ParallelMergeOptions.FullyBuffered));
        using (enumerator)
        {
            while (enumerator.MoveNext())
            {
                lookup.Add(enumerator.Current);
            }
            return lookup;
        }
    }

References System.Collections.Generic.Dictionary< TKey, TValue >.Add(), System.comparer, System.Linq.elementSelector, System.Collections.Generic.Dictionary< TKey, TValue >.GetEnumerator(), System.Linq.keySelector, and System.Linq.source.