This is a reimagination of Pythons popular Itertools module for C#. Albeit LINQ provides syntactically simple expressions there is still a few things that Itertools does really well whilst making sense in C#. Most of those things seem to evolve around the use of tuples or infinite collections. Features for enumerables are already decently covered in the System.Linq-namespace.

This app requires .NET Core. PowerShell is optional.

List of features ported.

Type	Nr	Method	Implemented	Comment
Infinite	1	count	✅
Infinite	2	cycle	✅
Infinite	3	repeat	-
Short termination	4	chain	-
Short termination	5	compress	✅
Short termination	6	dropwhile	✅
Short termination	7	groupby	-
Short termination	8	filter	✅	Also overloads index
Short termination	9	filterfalse	✅	Also overloads index
Short termination	10	islice	✅
Short termination	11	map	-
Short termination	12	starmap	✅
Short termination	13	tee	-	Due to language design return tuple is defined by generics rather than argument.
Short termination	14	takewhile	✅
Combinatoric	15	product	✅
Combinatoric	16	permutations	-
Combinatoric	17	combinations	🔨
Combinatoric	18	combinations_with_replacements	🔨

Planned changes

This library will probably include a few basic operations in addition to those listed above because of their implied use. However currying, partials and bind will not be included since the have great support through lambdas already.

Bind is already possible so no changes in relation to this:

(i, j) => valueFactory(i, "value0", j);

Currying is achieved with:

i => j => k => valueFactory(i, j, k);

Building, testing and running

PS> ./make.ps1
PS> ./make.ps1 test
PS> ./make.ps1 run

Example draft

For example a cartesian product can be described as:

    var libraries =
        from l in Libraries
        join m in Municipalities on l.MunicipalityId equals m.MunicipalityId
        from c in Countries
        where c.IsoCode equals m.IsoCode || "GP" == c.IsoCode
        select l;

Instead it's intended to make use of tuples for applying functions similar to parameter unpacking:

    var libraries =
        Product(Libraries, Municipalities, Countries)
        .Filter((item => item.Item1.MunicipalityId == item.Item2.MunicipalityId)
        .Filter(item => item.Item2.IsoCode == item.Item3.IsoCode || "GP" == item.Item3.IsoCode)
        .Select(t => t.Item1);