Method ScanRight

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ScanRight<TSource>(IEnumerable<TSource>, Func<TSource, TSource, TSource>)

Performs a right-associative scan (inclusive prefix) on a sequence of elements. This operator is the right-associative version of the Scan<TSource>(IEnumerable<TSource>, Func<TSource, TSource, TSource>) LINQ operator.

Declaration
public static IEnumerable<TSource> ScanRight<TSource>(this IEnumerable<TSource> source, Func<TSource, TSource, TSource> func)
Parameters
Type Name Description
IEnumerable<TSource> source

Source sequence.
Func<TSource, TSource, TSource> func

A right-associative accumulator function to be invoked on each element. Its first argument is the current value in the sequence; second argument is the previous accumulator value.
Returns
Type Description
IEnumerable<TSource>

The scanned sequence.
Type Parameters
Name Description
TSource

Type of elements in source sequence.
Remarks

This method is implemented by using deferred execution. However, source will be consumed in it's entirety immediately when first element of the returned sequence is consumed.

Examples

The following code example demonstrates how to execute a right-associative post-fix scan on a sequence using ScanRight.

var sequence = Enumerable.Range(1, 5)
    .Select(x => x.ToString());

// execute a scan of the sequence
var result = sequence
    .ScanRight((a, b) => $"({a}+{b})");

Console.WriteLine(
    "[ \"" +
    string.Join("\", \"", result) +
    "\" ]");

// This code produces the following output:
// [ "(1+(2+(3+(4+5))))", "(2+(3+(4+5)))", "(3+(4+5))", "(4+5)", "5" ]
Exceptions
Type Condition
ArgumentNullException

source or func is null.
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ScanRight<TSource, TAccumulate>(IEnumerable<TSource>, TAccumulate, Func<TSource, TAccumulate, TAccumulate>)

Performs a right-associative scan (inclusive prefix) on a sequence of elements. This operator is the right-associative version of the Scan<TSource>(IEnumerable<TSource>, Func<TSource, TSource, TSource>) LINQ operator.

Declaration
public static IEnumerable<TAccumulate> ScanRight<TSource, TAccumulate>(this IEnumerable<TSource> source, TAccumulate seed, Func<TSource, TAccumulate, TAccumulate> func)
Parameters
Type Name Description
IEnumerable<TSource> source

Source sequence.
TAccumulate seed

The initial accumulator value.
Func<TSource, TAccumulate, TAccumulate> func

A right-associative accumulator function to be invoked on each element. Its first argument is the current value in the sequence; second argument is the previous accumulator value.
Returns
Type Description
IEnumerable<TAccumulate>

The scanned sequence.
Type Parameters
Name Description
TSource

Type of elements in source sequence.
TAccumulate

Type of the state accumulator.
Remarks

This method is implemented by using deferred execution. However, source will be consumed in it's entirety immediately when first element of the returned sequence is consumed.

Examples

The following code example demonstrates how to execute a right-associative post-fix scan on a sequence using ScanRight.

var sequence = Enumerable.Range(1, 5);

// execute a scan of the sequence
var result = sequence
    .ScanRight(
        "6",
        (a, b) => $"({a}+{b})");

Console.WriteLine(
    "[ \"" +
    string.Join("\", \"", result) +
    "\" ]");

// This code produces the following output:
// [ "(1+(2+(3+(4+(5+6)))))", "(2+(3+(4+(5+6))))", "(3+(4+(5+6)))", "(4+(5+6))", "(5+6)", "6" ]
Exceptions
Type Condition
ArgumentNullException

source or func is null.