Library morelinq: what is missing in LINQ to Objects out of the box

I think many readers of the .Net blog know the name Jon Skeet . Especially after yesterday 's post of user SergeyT . Therefore, I will not repeat the comparison with Chuck Norris and the first place in karma on StackOverflow.com. But mentioning once again about his wonderful book “C # In Depth” will definitely not be superfluous. LINQ in general and LINQ to Objects in particular are central to it. John very thoroughly describes all the features of the C # language and the .Net platform, which made possible the emergence of LINQ in its current form, as well as the details of its implementation. It was after reading this book that I began to actively use LINQ to Objects in my projects. However, the standard library lacks some highly needed operators. Fortunately, John Skeet corrected this misunderstanding. So there was a small, but very useful library morelinq . And since the end of last year it is available as a NuGet package .

Morelinq library operators

Batch	Turns one sequence into several sequences of n elements.
Concat	Attaches an item to a collection or a collection to an item.
Consume	"Absorbs" the collection, without producing any action on the elements.
DistinctBy	Returns only unique elements (by specified criteria).
Equizip	Creates a new sequence, where each element is created based on the corresponding elements of the original sequences. If sequences have different numbers of elements, an InvalidOperationException will be thrown.
ExceptBy	Returns the elements of the first sequence that are not contained in the second (by the given criterion).
ForEach	Performs an action on each element of the sequence.
Generate	Generates sequences on the initial element and the function generator.
GenerateByIndex	Generates a sequence of item indices.
Groupadjacent	Similar to GroupBy, but only consecutive items fall into the group.
Index	Returns a sequence of index-value pairs.
Maxby	Returns the maximum element of a sequence according to a given criterion.
Minby	Returns the minimum element of a sequence according to a given criterion.
Pad	If the number of elements in the sequence is less than the specified number, the sequence complements the default values ​​to the specified number.
Pairwise	Returns a sequence of function results for the current and previous elements (does not apply to the first element).
Pipe	Returns the original sequence by performing an Action on each element.
Prepend	Complements the beginning of the collection with a specified element.
PreScan	Returns the sequence of the original length, in which the Nth element is determined by applying the specified transform to N-1 elements.
Scan	Returns the sequence of the original length, in which the Nth element is determined by applying the specified transform to N elements.
SingleOrFallback	Returns the only element of a sequence, or the result of the specified delegate if the sequence is empty.
SkipUntil	Skips the elements of the original sequence until the specified condition is true. The current item will be the last skipped.
Split	Splits a sequence with a specified delimiter (returns a sequence of sequences).
TakeEvery	Returns every Nth element of the source sequence.
TakeLast	Returns the last N elements of the source sequence.
TakeUntil	Returns the elements of the original sequence until the specified condition becomes true. The current item will be the last returned item.
Todatatable	Allows you to convert a sequence to a new DataTable or fill the existing one. It is possible to set the lamdas to get the values ​​for the table fields from the source element.
ToDelimitedString	Converts a sequence to a delimited string (something that usually has to be done through a tedious Aggregate).
Tohashset	Returns HashSet 〈T & kang; from the original elements.
Zip	Same as EquiZip, but the length of the resulting sequence will be equal to the length of the smallest of the original.
ZipLongest	Same as EquiZip, but the length of the resulting sequence will be equal to the length of the largest of the original ones (the default value will be used as missing values).

Most operators are overloaded for greater flexibility of use (for example, you can specify your IComparer, etc.). In addition to the listed operators, there are two more debugging ones - AssertCount (check the number of sequence elements) and Trace (displays all elements in a debug console).

Together with the source code of the library there is excellent documentation in the MSDN style, in which all operators are described in detail, their parameters and examples of use are available. There are also comments in the source code.
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In conclusion, I would like to draw readers' attention to the two other libraries of authorship by John Skit - MiscUtils and NodaTime ( NuGet Package ). The latter is particularly interesting - the library is designed to work with date / time. John has been doing it for the last few years and finally released version 1.0 in November last year. In his blog, you can read a lot of interesting things about what the standard .Net classes are bad for these purposes and what underwater rakes await a developer who is seriously working with time.

UPD: Translation of an article about NodaTime .

UPD2: I did not use the word “projection” in the article, as I think it is not used in the Russian-speaking community. I would like to see your opinion in the survey and comments.