Linqor

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.

Usage

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 ]

Difference to LINQ API

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.

Why OrderedEnumerable<T, TKey> class and not IOrderedEnumerable<T>

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>.