Method Window

Window<TSource, TResult>(IEnumerable<TSource>, int, ReadOnlySpanFunc<TSource, TResult>)

Processes a sequence into a series of subsequences representing a windowed subset of the original, and then projecting them into a new form.

Declaration

public static IEnumerable<TResult> Window<TSource, TResult>(this IEnumerable<TSource> source, int size, SuperEnumerable.ReadOnlySpanFunc<TSource, TResult> selector)

Parameters

Type	Name	Description
IEnumerable<TSource>	source	The sequence to evaluate a sliding window over.
int	size	The size (number of elements) in each window.
SuperEnumerable.ReadOnlySpanFunc<TSource, TResult>	selector	A transform function to apply to each window.

Returns

Type	Description
IEnumerable<TResult>	An IEnumerable<T> whose elements are the result of invoking the transform function on each window of source.

Type Parameters

Name	Description
TSource	The type of the elements of selector.
TResult	The type of the value return by selector.

Remarks

A window can contain fewer elements than size, especially as it slides over the start of the sequence.

In this overload of Window, a single array of length size is allocated as a buffer for all subsequences.

This operator uses deferred execution and streams its results.

Exceptions

Type	Condition
ArgumentNullException	source is null.
ArgumentOutOfRangeException	size is below 1.

Window<TSource, TResult>(IEnumerable<TSource>, TSource[], ReadOnlySpanFunc<TSource, TResult>)

Processes a sequence into a series of subsequences representing a windowed subset of the original, and then projecting them into a new form.

Declaration

public static IEnumerable<TResult> Window<TSource, TResult>(this IEnumerable<TSource> source, TSource[] array, SuperEnumerable.ReadOnlySpanFunc<TSource, TResult> selector)

Parameters

Type	Name	Description
IEnumerable<TSource>	source	The sequence to evaluate a sliding window over.
TSource[]	array	An array to use as a buffer for each subsequence.
SuperEnumerable.ReadOnlySpanFunc<TSource, TResult>	selector	A transform function to apply to each window.

Returns

Type	Description
IEnumerable<TResult>	An IEnumerable<T> whose elements are the result of invoking the transform function on each window of source.

Type Parameters

Name	Description
TSource	The type of the elements of selector.
TResult	The type of the value return by selector.

Remarks

A window can contain fewer elements than array.Length, especially as it slides over the start of the sequence.

In this overload of Window, array is used as a common buffer for all subsequences.

This operator uses deferred execution and streams its results.

Exceptions

Type	Condition
ArgumentNullException	source is null.

Window<TSource, TResult>(IEnumerable<TSource>, TSource[], int, ReadOnlySpanFunc<TSource, TResult>)

Processes a sequence into a series of subsequences representing a windowed subset of the original, and then projecting them into a new form.

Declaration

public static IEnumerable<TResult> Window<TSource, TResult>(this IEnumerable<TSource> source, TSource[] array, int size, SuperEnumerable.ReadOnlySpanFunc<TSource, TResult> selector)

Parameters

Type	Name	Description
IEnumerable<TSource>	source	The sequence to evaluate a sliding window over.
TSource[]	array	An array to use as a buffer for each subsequence.
int	size	The size (number of elements) in each window.
SuperEnumerable.ReadOnlySpanFunc<TSource, TResult>	selector	A transform function to apply to each window.

Returns

Type	Description
IEnumerable<TResult>	An IEnumerable<T> whose elements are the result of invoking the transform function on each window of source.

Type Parameters

Name	Description
TSource	The type of the elements of selector.
TResult	The type of the value return by selector.

Remarks

A window can contain fewer elements than size, especially as it slides over the start of the sequence.

In this overload of Window, array is used as a common buffer for all subsequences.
This overload is provided to ease usage of common buffers, such as those rented from ArrayPool<T>, which may return an array larger than requested.

This operator uses deferred execution and streams its results.

Exceptions

Type	Condition
ArgumentNullException	source is null.
ArgumentOutOfRangeException	size is below 1 or above array.Length.

Window<TSource>(IEnumerable<TSource>, int)

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

Declaration

public static IEnumerable<IList<TSource>> Window<TSource>(this IEnumerable<TSource> source, int size)

Parameters

Type	Name	Description
IEnumerable<TSource>	source	The sequence to evaluate a sliding window over
int	size	The size (number of elements) in each window

Returns

Type	Description
IEnumerable<IList<TSource>>	A series of sequences representing each sliding window subsequence

Type Parameters

Name	Description
TSource	The type of the elements of the source sequence

Remarks

The number of sequences returned is: Max(0, source.Count() - size + 1)
Returned subsequences are buffered, but the overall operation is streamed.

Examples

The following code example demonstrates how to generate a sliding window over a sequence using Window.

var sequence = Enumerable.Range(1, 10);

// Get a sliding window over the sequence
var result = sequence.Window(3);

Console.WriteLine(
    "[" + Environment.NewLine + 
    string.Join(
        ", " + Environment.NewLine,
        result.Select(c => "   [" + string.Join(", ", c) + "]")) +
    Environment.NewLine + "]");

// This code produces the following output:
// [
//    [1, 2, 3],
//    [2, 3, 4],
//    [3, 4, 5],
//    [4, 5, 6],
//    [5, 6, 7],
//    [6, 7, 8],
//    [7, 8, 9],
//    [8, 9, 10]
// ]

Exceptions

Type	Condition
ArgumentNullException	source is null.
ArgumentOutOfRangeException	size is below 1.