Linq extensions for ordered sequences. They have better perfomance in comparison to standard extensions. They don't enumerate entire sequences into HashSet<T> or lookup. With these you can lazily handle very large or even infinite sequences as long as they're ordered.
Concat, Distinct, Except, GroupBy, GroupJoin, Intersect, Join, SelectMany and Union are available.
Cast IEnumerable<T> to OrderedEnumberable<T, TKey> by calling AsOrderedBy<T, TKey>. Use extensions as usual.
new[] { 1, 1, 2, 2, 2 }.AsOrderedBy(x => x).Distinct(); // [ 1, 2 ]
new[] { 1, 3, 5 }.AsOrderedBy(x => x).Concat(new[] { 2, 4, 6 }.AsOrderedBy(x => x)); // [ 1, 2, 3, 4, 5, 6 ]No IComparer<T> comparer or Func<T, TKey> keySelector parameters. Ones from OrderedEnumerable<T, TKey> are used instead.
GroupJoin and Join require additional Func<TResult, TKey> resultKeySelector parameter.
SelectMany requires additional OrderedEnumerable<TResult, TResultKey> seed parameter.
They're needed to construct OrderedEnumerable<TResult, TKey> result.
Algorithms require IComparer<T> that was used to order the enumerable. Sadly System.Linq.OrderedEnumerable is internal and IOrderedEnumerable<T> doesn't have IComparer<T>.