Method ScanBy

ScanBy<TSource, TKey, TState>(IAsyncEnumerable<TSource>, Func<TSource, TKey>, Func<TKey, TState>, Func<TState, TKey, TSource, TState>)

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

Declaration

public static IAsyncEnumerable<(TKey key, TState state)> ScanBy<TSource, TKey, TState>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TKey, TState> seedSelector, Func<TState, TKey, TSource, TState> accumulator)

Parameters

Type	Name	Description
IAsyncEnumerable<TSource>	source	The source sequence.
Func<TSource, TKey>	keySelector	A function that returns the key given an element.
Func<TKey, TState>	seedSelector	A function to determine the initial value for the accumulator that is invoked once per key encountered.
Func<TState, TKey, TSource, TState>	accumulator	An accumulator function invoked for each element.

Returns

Type	Description
IAsyncEnumerable<(TKey key, TState state)>	A sequence of keys paired with intermediate accumulator states.

Type Parameters

Name	Description
TSource	Type of the elements of the source sequence.
TKey	The type of the key.
TState	Type of the state.

Exceptions

Type	Condition
ArgumentNullException	source is null.
ArgumentNullException	keySelector is null.
ArgumentNullException	seedSelector is null.
ArgumentNullException	accumulator is null.

ScanBy<TSource, TKey, TState>(IAsyncEnumerable<TSource>, Func<TSource, ValueTask<TKey>>, Func<TKey, ValueTask<TState>>, Func<TState, TKey, TSource, ValueTask<TState>>)

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

Declaration

public static IAsyncEnumerable<(TKey key, TState state)> ScanBy<TSource, TKey, TState>(this IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<TKey>> keySelector, Func<TKey, ValueTask<TState>> seedSelector, Func<TState, TKey, TSource, ValueTask<TState>> accumulator)

Parameters

Type	Name	Description
IAsyncEnumerable<TSource>	source	The source sequence.
Func<TSource, ValueTask<TKey>>	keySelector	A function that returns the key given an element.
Func<TKey, ValueTask<TState>>	seedSelector	A function to determine the initial value for the accumulator that is invoked once per key encountered.
Func<TState, TKey, TSource, ValueTask<TState>>	accumulator	An accumulator function invoked for each element.

Returns

Type	Description
IAsyncEnumerable<(TKey key, TState state)>	A sequence of keys paired with intermediate accumulator states.

Type Parameters

Name	Description
TSource	Type of the elements of the source sequence.
TKey	The type of the key.
TState	Type of the state.

Exceptions

Type	Condition
ArgumentNullException	source is null.
ArgumentNullException	keySelector is null.
ArgumentNullException	seedSelector is null.
ArgumentNullException	accumulator is null.

ScanBy<TSource, TKey, TState>(IAsyncEnumerable<TSource>, Func<TSource, CancellationToken, ValueTask<TKey>>, Func<TKey, CancellationToken, ValueTask<TState>>, Func<TState, TKey, TSource, CancellationToken, ValueTask<TState>>)

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

Declaration

public static IAsyncEnumerable<(TKey key, TState state)> ScanBy<TSource, TKey, TState>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<TKey>> keySelector, Func<TKey, CancellationToken, ValueTask<TState>> seedSelector, Func<TState, TKey, TSource, CancellationToken, ValueTask<TState>> accumulator)

Parameters

Type	Name	Description
IAsyncEnumerable<TSource>	source	The source sequence.
Func<TSource, CancellationToken, ValueTask<TKey>>	keySelector	A function that returns the key given an element.
Func<TKey, CancellationToken, ValueTask<TState>>	seedSelector	A function to determine the initial value for the accumulator that is invoked once per key encountered.
Func<TState, TKey, TSource, CancellationToken, ValueTask<TState>>	accumulator	An accumulator function invoked for each element.

Returns

Type	Description
IAsyncEnumerable<(TKey key, TState state)>	A sequence of keys paired with intermediate accumulator states.

Type Parameters

Name	Description
TSource	Type of the elements of the source sequence.
TKey	The type of the key.
TState	Type of the state.

Exceptions

Type	Condition
ArgumentNullException	source is null.
ArgumentNullException	keySelector is null.
ArgumentNullException	seedSelector is null.
ArgumentNullException	accumulator is null.

ScanBy<TSource, TKey, TState>(IAsyncEnumerable<TSource>, Func<TSource, TKey>, Func<TKey, TState>, Func<TState, TKey, TSource, TState>, IEqualityComparer<TKey>?)

Applies an accumulator function over sequence element keys, returning the keys along with intermediate accumulator states. An additional parameter specifies the comparer to use to compare keys.

Declaration

public static IAsyncEnumerable<(TKey key, TState state)> ScanBy<TSource, TKey, TState>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TKey, TState> seedSelector, Func<TState, TKey, TSource, TState> accumulator, IEqualityComparer<TKey>? comparer)

Parameters

Type	Name	Description
IAsyncEnumerable<TSource>	source	The source sequence.
Func<TSource, TKey>	keySelector	A function that returns the key given an element.
Func<TKey, TState>	seedSelector	A function to determine the initial value for the accumulator that is invoked once per key encountered.
Func<TState, TKey, TSource, TState>	accumulator	An accumulator function invoked for each element.
IEqualityComparer<TKey>	comparer	The equality comparer to use to determine whether or not keys are equal. If null, the default equality comparer for TSource is used.

Returns

Type	Description
IAsyncEnumerable<(TKey key, TState state)>	A sequence of keys paired with intermediate accumulator states.

Type Parameters

Name	Description
TSource	Type of the elements of the source sequence.
TKey	The type of the key.
TState	Type of the state.

Exceptions

Type	Condition
ArgumentNullException	source is null.
ArgumentNullException	keySelector is null.
ArgumentNullException	seedSelector is null.
ArgumentNullException	accumulator is null.

ScanBy<TSource, TKey, TState>(IAsyncEnumerable<TSource>, Func<TSource, ValueTask<TKey>>, Func<TKey, ValueTask<TState>>, Func<TState, TKey, TSource, ValueTask<TState>>, IEqualityComparer<TKey>?)

Applies an accumulator function over sequence element keys, returning the keys along with intermediate accumulator states. An additional parameter specifies the comparer to use to compare keys.

Declaration

public static IAsyncEnumerable<(TKey key, TState state)> ScanBy<TSource, TKey, TState>(this IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<TKey>> keySelector, Func<TKey, ValueTask<TState>> seedSelector, Func<TState, TKey, TSource, ValueTask<TState>> accumulator, IEqualityComparer<TKey>? comparer)

Parameters

Type	Name	Description
IAsyncEnumerable<TSource>	source	The source sequence.
Func<TSource, ValueTask<TKey>>	keySelector	A function that returns the key given an element.
Func<TKey, ValueTask<TState>>	seedSelector	A function to determine the initial value for the accumulator that is invoked once per key encountered.
Func<TState, TKey, TSource, ValueTask<TState>>	accumulator	An accumulator function invoked for each element.
IEqualityComparer<TKey>	comparer	The equality comparer to use to determine whether or not keys are equal. If null, the default equality comparer for TSource is used.

Returns

Type	Description
IAsyncEnumerable<(TKey key, TState state)>	A sequence of keys paired with intermediate accumulator states.

Type Parameters

Name	Description
TSource	Type of the elements of the source sequence.
TKey	The type of the key.
TState	Type of the state.

Exceptions

Type	Condition
ArgumentNullException	source is null.
ArgumentNullException	keySelector is null.
ArgumentNullException	seedSelector is null.
ArgumentNullException	accumulator is null.

ScanBy<TSource, TKey, TState>(IAsyncEnumerable<TSource>, Func<TSource, CancellationToken, ValueTask<TKey>>, Func<TKey, CancellationToken, ValueTask<TState>>, Func<TState, TKey, TSource, CancellationToken, ValueTask<TState>>, IEqualityComparer<TKey>?)

Applies an accumulator function over sequence element keys, returning the keys along with intermediate accumulator states. An additional parameter specifies the comparer to use to compare keys.

Declaration

public static IAsyncEnumerable<(TKey key, TState state)> ScanBy<TSource, TKey, TState>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<TKey>> keySelector, Func<TKey, CancellationToken, ValueTask<TState>> seedSelector, Func<TState, TKey, TSource, CancellationToken, ValueTask<TState>> accumulator, IEqualityComparer<TKey>? comparer)

Parameters

Type	Name	Description
IAsyncEnumerable<TSource>	source	The source sequence.
Func<TSource, CancellationToken, ValueTask<TKey>>	keySelector	A function that returns the key given an element.
Func<TKey, CancellationToken, ValueTask<TState>>	seedSelector	A function to determine the initial value for the accumulator that is invoked once per key encountered.
Func<TState, TKey, TSource, CancellationToken, ValueTask<TState>>	accumulator	An accumulator function invoked for each element.
IEqualityComparer<TKey>	comparer	The equality comparer to use to determine whether or not keys are equal. If null, the default equality comparer for TSource is used.

Returns

Type	Description
IAsyncEnumerable<(TKey key, TState state)>	A sequence of keys paired with intermediate accumulator states.

Type Parameters

Name	Description
TSource	Type of the elements of the source sequence.
TKey	The type of the key.
TState	Type of the state.

Exceptions

Type	Condition
ArgumentNullException	source is null.
ArgumentNullException	keySelector is null.
ArgumentNullException	seedSelector is null.
ArgumentNullException	accumulator is null.