SuperLinq 4.1.0-preview.2

SuperLinq

LINQ to Objects is missing a few desirable features.

This project enhances LINQ to Objects with extra methods, in a manner which keeps to the spirit of LINQ.

SuperLinq is available for download and installation as NuGet packages.

Usage

SuperLinq can be used in one of two ways. The simplest is to just import the SuperLinq namespace and all extension methods become instantly available for you to use on the types they extend (typically some instantiation of IEnumerable<T>).

Apart from extension methods, SuperLinq also offers regular static method that generate (instead of operating on) sequences, like Unfold, Random, Sequence and others.

Migration from MoreLINQ

In most case, migration should be easy:

1. Remove the nuget reference to MoreLINQ and add a reference to SuperLinq.
2. Replace any using MoreLinq; with using SuperLinq;
3. Remove any using MoreLinq.Extensions.*

This is because SuperLinq has been updated to be side-by-side compatible with .NET Core 3.1 and .NET 5.0/6.0.

Breaking Changes

Framework Support

Support for earlier frameworks has been dropped. The earliest version supported by SuperLinq is .NET Core 3.1.

System.Interactive

SuperLinq now holds a dependency on System.Interactive. This is because some methods from SuperLinq overlap functions with the same and occasionally the same name. To reduce conflicts, SuperLinq will defer to System.Interactive for these methods when possible. Methods removed include: .Repeat(), .Scan(), .ForEach(), .Memoize().

Acquire

Acquire has been removed. It was used internally to support other operators, but improved data structures have been introduced to better support them.

AwaitQuery/Observable/Experimental Operators

These operators have been removed, as they do not fit the model of the other SuperLinq operators.

Backsert

This method has been obsoleted in favor of a new overload for .Insert() that receives an Index parameter, which covers the same behavior.

Batch

The .Batch() method has been obsoleted in favor of the .NET method .Chunk() or the System.Interactive method .Buffer().

CountDown

An additional overload has been added that returns a stream of (TSource item, int? count).

Lag/Lead

Additional overloads have been added for Lag/Lead that return streams of (TSource cur, TSource lag/lead).

MaxBy/MinBy

MaxBy and MinBy have been removed. These methods are superceded by PartialSort, and conflict with new .NET 6.0 MaxBy/MinBy methods that operate slightly differently.

Pairwise

Pairwise has been removed as it overlaps behavior with both .Lag() and .Window()

PartialSort

The sorting behavior of .PartialSort() has been changed slightly, as it now uses a stable sorting algorithm. This means that items that have the same value (or key) will return in the same order that they were originally encountered in the stream. This is a minor change from old sorting behavior.

Rank

The behavior and return type of Rank has been updated:

• Previously, Rank would rank according the highest value by default, opposite to the sorting.
  • Now, Rank ranks according to the lowest value, matching the sorting
• Previously, Rank would return a simple list of integers matching the original items
  • Now, Rank returns a sorted list of items with their rank
• Previously, Rank would rank each group with a sequential rank value
  • Now, Rank ranks each group according to how many total items have been encountered in the stream thus far.
  • DenseRank will rank each group with a seqential value.

All of these changes are made to bring Rank/DenseRank with the behavior expressed for Rank/DenseRank in SQL systems (Sql Server, PostgreSQL, etc.)

RunLengthEncode

The return type has been changed from a stream of KeyValuePair<T, int> to a stream of (T value, int count)

Scan

The .Scan() method has been renamed to .ScanEx() in order to avoid conflict with the System.Interactive version of the method. However, the behavior of the System.Interactive version differs slightly in that it does not return the seed/first element. The new .ScanEx() method maintains the original behavior.

.NET Versions

Base library is supported on .NET Core 3.1 and .NET 5.0+.

Operators

Aggregate

Applies multiple accumulators sequentially in a single pass over a sequence.

This method has 7 overloads.

AggregateRight

Applies a right-associative accumulator function over a sequence. This operator is the right-associative version of the Aggregate LINQ operator.

This method has 3 overloads.

AtLeast

Determines whether or not the number of elements in the sequence is greater than or equal to the given integer.

AtMost

Determines whether or not the number of elements in the sequence is lesser than or equal to the given integer.

Backsert

Inserts the elements of a sequence into another sequence at a specified index from the tail of the sequence, where zero always represents the last position, one represents the second-last element, two represents the third-last element and so on.

(Obsoleted in favor of Insert)

Cartesian

Returns the Cartesian product of two or more sequences by combining each element from the sequences and applying a user-defined projection to the set.

This method has 7 overloads.

Choose

Applies a function to each element of the source sequence and returns a new sequence of result elements for source elements where the function returns a couple (2-tuple) having a true as its first element and result as the second.

CompareCount

Compares two sequences and returns an integer that indicates whether the first sequence has fewer, the same or more elements than the second sequence.

Consume

Completely consumes the given sequence. This method uses immediate execution, and doesn't store any data during execution

CountBetween

Determines whether or not the number of elements in the sequence is between an inclusive range of minimum and maximum integers.

CountBy

Applies a key-generating function to each element of a sequence and returns a sequence of unique keys and their number of occurrences in the original sequence.

This method has 2 overloads.

CountDown

Provides a countdown counter for a given count of elements at the tail of the sequence where zero always represents the last element, one represents the second-last element, two represents the third-last element and so on.

This method has 2 overloads.

DenseRank

Ranks each item in the sequence with ascending ordering according to the number of unique values encountered.

This method has 2 overloads.

DenseRankBy

Ranks each item in the sequence with ascending ordering according to the number of unique values encountered.

This method has 2 overloads.

DistinctBy (Hidden in .NET 6 in favor of the Framework version)

Returns all distinct elements of the given source, where "distinctness" is determined via a projection and the default equality comparer for the projected type.

This method has 2 overloads.

ElementAt (pre-.NET 6)

Returns the element at a specified index in a sequence.

Backport from official sources to .net core 3.1 and .net 5.

EndsWith

Determines whether the end of the first sequence is equivalent to the second sequence.

This method has 2 overloads.

EquiZip

Returns a projection of tuples, where each tuple contains the N-th element from each of the argument sequences. An exception is thrown if the input sequences are of different lengths.

This method has 3 overloads.

Exactly

Determines whether or not the number of elements in the sequence is equals to the given integer.

ExceptBy (Hidden in .NET 6 in favor of the Framework version)

Returns the set of elements in the first sequence which aren't in the second sequence, according to a given key selector.

This method has 2 overloads.

Exclude

Excludes elements from a sequence starting at a given index

FallbackIfEmpty

Returns the elements of a sequence and falls back to another if the original sequence is empty.

This method has 2 overloads.

FillBackward

Returns a sequence with each null reference or value in the source replaced with the following non-null reference or value in that sequence.

This method has 3 overloads.

FillForward

Returns a sequence with each null reference or value in the source replaced with the previous non-null reference or value seen in that sequence.

This method has 3 overloads.

Flatten

Flattens a sequence containing arbitrarily-nested sequences.

This method has 3 overloads.

Fold

Returns the result of applying a function to a sequence with 1 to 16 elements.

This method has 16 overloads.

From

Returns a sequence containing the values resulting from invoking (in order) each function in the source sequence of functions.

This method has 4 overloads.

FullGroupJoin

Performs a Full Group Join between the and sequences.

This method has 4 overloads.

FullJoin

Performs a full outer join between two sequences.

This method has 4 overloads.

Generate

Returns a sequence of values consecutively generated by a generator function

GenerateByIndex

Returns a sequence of values based on indexes

GetShortestPath

Finds the shortest path between two points, using either Dijkstra's algorithm or the A* algorithm (depending on whether a heuristic value is provided when getting state neighbors).

The underlying map can be a plane, a graph, or any other state system provided by the consumer, since traversal from one state to the next is done by the consumer in the getNeighbors functor.

This method has 4 overloads.

GetShortestPathCost

Finds the cost of the shortest path between two points, using either Dijkstra's algorithm or the A* algorithm (depending on whether a heuristic value is provided when getting state neighbors).

The underlying map can be a plane, a graph, or any other state system provided by the consumer, since traversal from one state to the next is done by the consumer in the getNeighbors functor.

This method has 4 overloads.

GetShortestPaths

Finds the shortest path from a starting point to every other point in the map, using either Dijkstra's algorithm.

The underlying map can be a plane, a graph, or any other state system provided by the consumer, since traversal from one state to the next is done by the consumer in the getNeighbors functor. The map must have a finite number of states in order for this method to complete.

This method has 2 overloads.

GroupAdjacent

Groups the adjacent elements of a sequence according to a specified key selector function.

This method has 6 overloads.

Index

Returns a sequence of where the key is the zero-based index of the value in the source sequence.

This method has 2 overloads.

IndexBy

Applies a key-generating function to each element of a sequence and returns a sequence that contains the elements of the original sequence as well its key and index inside the group of its key. An additional argument specifies a comparer to use for testing equivalence of keys.

This method has 2 overloads.

Insert

Inserts the elements of a sequence into another sequence at a specified index.

This method has 2 overloads.

Interleave

Interleaves the elements of two or more sequences into a single sequence, skipping sequences as they are consumed.

This method has 2 overloads.

Lag

Produces a projection of a sequence by evaluating pairs of elements separated by a negative offset.

This method has 2 overloads.

Lead

Produces a projection of a sequence by evaluating pairs of elements separated by a positive offset.

This method has 2 overloads.

LeftJoin

Performs a left outer join between two sequences.

This method has 4 overloads.

Move

Returns a sequence with a range of elements in the source sequence moved to a new offset.

OrderBy

Sorts the elements of a sequence in a particular direction (ascending, descending) according to a key.

This method has 2 overloads.

OrderedMerge

Merges two ordered sequences into one. Where the elements equal in both sequences, the element from the first sequence is returned in the resulting sequence.

This method has 7 overloads.

Pad

Pads a sequence with default values if it is narrower (shorter in length) than a given width.

This method has 3 overloads.

PadStart

Pads a sequence with default values in the beginning if it is narrower (shorter in length) than a given width.

This method has 3 overloads.

PartialSort

Combines OrderBy (where element is key) and Take in a single operation.

This method has 4 overloads.

PartialSortBy

Combines OrderBy and Take in a single operation.

This method has 4 overloads.

Partition

Partitions a sequence by a predicate, or a grouping by Boolean keys or up to 3 sets of keys.

This method has 10 overloads.

Permutations

Generates a sequence of lists that represent the permutations of the original sequence

Pipe

Executes the given action on each element in the source sequence and yields it

PreScan

Performs a pre-scan (exclusive prefix sum) on a sequence of elements

Random

Returns an infinite sequence of random integers using the standard .NET random number generator.

This method has 6 overloads.

RandomDouble

Returns an infinite sequence of random double values between 0.0 and 1.0.

This method has 2 overloads.

RandomSubset

Returns a sequence of a specified size of random elements from the original sequence.

This method has 2 overloads.

Rank

Ranks each item in the sequence with ascending ordering according to the total number of items encountered.

This method has 2 overloads.

RankBy

Ranks each item in the sequence with ascending ordering according to the total number of items encountered.

This method has 2 overloads.

Repeat

Repeats the sequence indefinitely or a specific number of times.

This method has 2 overloads.

Return

Returns a single-element sequence containing the item provided.

RightJoin

Performs a right outer join between two sequences.

This method has 4 overloads.

RunLengthEncode

Run-length encodes a sequence by converting consecutive instances of the same element into a KeyValuePair<T, int> representing the item and its occurrence count.

This method has 2 overloads.

ScanBy

Applies an accumulator function over sequence element keys, returning the keys along with intermediate accumulator states.

This method has 2 overloads.

ScanEx

Peforms a scan (inclusive prefix sum) on a sequence of elements.

This method has 2 overloads.

ScanRight

Peforms a right-associative scan (inclusive prefix) on a sequence of elements. This operator is the right-associative version of the Scan operator.

This method has 2 overloads.

Segment

Divides a sequence into multiple sequences by using a segment detector based on the original sequence.

This method has 3 overloads.

Sequence

Generates a sequence of integral numbers within the (inclusive) specified range.

This method has 2 overloads.

Shuffle

Returns a sequence of elements in random order from the original sequence.

This method has 2 overloads.

SkipUntil

Skips items from the input sequence until the given predicate returns true when applied to the current source item; that item will be the last skipped

Slice

Extracts elements from a sequence at a particular zero-based starting index

SortedMerge

Merges two or more sequences that are in a common order (either ascending or descending) into a single sequence that preserves that order.

This method has 4 overloads.

SortedMergeDescending

Merges two or more sequences that are in a common order (either ascending or descending) into a single sequence that preserves that order.

This method has 2 overloads.

Split

Splits the source sequence by a separator.

This method has 12 overloads.

StartsWith

Determines whether the beginning of the first sequence is equivalent to the second sequence.

This method has 2 overloads.

Subsets

Returns a sequence of representing all of the subsets of any size that are part of the original sequence.

This method has 2 overloads.

TagFirstLast

Returns a sequence resulting from applying a function to each element in the source sequence with additional parameters indicating whether the element is the first and/or last of the sequence

Take (pre-.NET 6)

Returns a specified range of contiguous elements from a sequence using the range operator.

Backport from official sources to .net core 3.1 and .net 5.

TakeEvery

Returns every N-th element of a source sequence

TakeUntil

Returns items from the input sequence until the given predicate returns true when applied to the current source item; that item will be the last returned

ThenBy

Performs a subsequent ordering of elements in a sequence in a particular direction (ascending, descending) according to a key.

This method has 2 overloads.

ToArrayByIndex

Creates an array from an IEnumerable<T> where a function is used to determine the index at which an element will be placed in the array.

This method has 6 overloads.

ToDataTable

Appends elements in the sequence as rows of a given object with a set of lambda expressions specifying which members (property or field) of each element in the sequence will supply the column values.

This method has 4 overloads.

ToDelimitedString

Creates a delimited string from a sequence of values. The delimiter used depends on the current culture of the executing thread.

This method has 15 overloads.

ToDictionary

Creates a dictionary from a sequence of key-value pair elements or tuples of 2.

This method has 4 overloads.

ToLookup

Creates a lookup from a sequence of key-value pair elements or tuples of 2.

This method has 4 overloads.

Transpose

Transposes the rows of a sequence into columns.

TraverseBreadthFirst

Traverses a tree in a breadth-first fashion, starting at a root node and using a user-defined function to get the children at each node of the tree.

TraverseDepthFirst

Traverses a tree in a depth-first fashion, starting at a root node and using a user-defined function to get the children at each node of the tree.

Trace

Traces the elements of a source sequence for diagnostics.

This method has 3 overloads.

TrySingle

Returns the only element of a sequence that has just one element. If the sequence has zero or multiple elements, then returns a user-defined value that indicates the cardinality of the result sequence.

This method has 2 overloads.

Unfold

Returns a sequence generated by applying a state to the generator function, and from its result, determines if the sequence should have a next element and its value, and the next state in the recursive call.

Where

Returns a sequence filtered by a matching sequence of boolean values. Useful if you have a fixed list of boolean values that should be used to filter multiple similar sequences.

Window

Processes a sequence into a series of subsequences representing a windowed subset of the original

WindowLeft

Creates a left-aligned sliding window over the source sequence of a given size.

WindowRight

Creates a right-aligned sliding window over the source sequence of a given size.

ZipLongest

Returns a projection of tuples, where each tuple contains the N-th element from each of the argument sequences. The resulting sequence will always be as long as the longest of input sequences where the default value of each of the shorter sequence element types is used for padding.

This method has 3 overloads.

ZipMap

Returns a sequence of tuples, where each tuple contains both the original element as well as a projection from that element.

ZipShortest

Returns a projection of tuples, where each tuple contains the N-th element from each of the argument sequences. The resulting sequence is as short as the shortest input sequence.

This method has 3 overloads.