Method Partition

Partition<T>(IAsyncEnumerable<T>, Func<T, bool>, CancellationToken)

Partitions or splits a sequence in two using a predicate.

Declaration

public static ValueTask<(IEnumerable<T> True, IEnumerable<T> False)> Partition<T>(this IAsyncEnumerable<T> source, Func<T, bool> predicate, CancellationToken cancellationToken = default)

Parameters

Type	Name	Description
IAsyncEnumerable<T>	source	The source sequence.
Func<T, bool>	predicate	The predicate function.
CancellationToken	cancellationToken	The optional cancellation token to be used for cancelling the sequence at any time.

Returns

Type	Description
ValueTask<(IEnumerable<T> True, IEnumerable<T> False)>	A tuple of elements satisfying the predicate and those that do not, respectively.

Type Parameters

Name	Description
T	Type of source elements.

Examples

var (evens, odds) =
    Enumerable.Range(0, 10).Partition(x => x % 2 == 0);

    The <code>evens</code> variable, when iterated over, will yield 0, 2, 4, 6
    and then 8. The <code>odds</code> variable, when iterated over, will yield
    1, 3, 5, 7 and then 9.

Exceptions

Type	Condition
ArgumentNullException	source is null

Partition<T, TResult>(IAsyncEnumerable<T>, Func<T, bool>, Func<IEnumerable<T>, IEnumerable<T>, TResult>, CancellationToken)

Partitions or splits a sequence in two using a predicate and then projects a result from the two.

Declaration

public static ValueTask<TResult> Partition<T, TResult>(this IAsyncEnumerable<T> source, Func<T, bool> predicate, Func<IEnumerable<T>, IEnumerable<T>, TResult> resultSelector, CancellationToken cancellationToken = default)

Parameters

Type	Name	Description
IAsyncEnumerable<T>	source	The source sequence.
Func<T, bool>	predicate	The predicate function.
Func<IEnumerable<T>, IEnumerable<T>, TResult>	resultSelector	Function that projects the result from sequences of elements that satisfy the predicate and those that do not, respectively, passed as arguments.
CancellationToken	cancellationToken	The optional cancellation token to be used for cancelling the sequence at any time.

Returns

Type	Description
ValueTask<TResult>	The return value from resultSelector.

Type Parameters

Name	Description
T	Type of source elements.
TResult	Type of the result.

Examples

var (evens, odds) =
    Enumerable.Range(0, 10)
              .Partition(x => x % 2 == 0, ValueTuple.Create);

    The <code>evens</code> variable, when iterated over, will yield 0, 2, 4, 6
    and then 8. The <code>odds</code> variable, when iterated over, will yield
    1, 3, 5, 7 and then 9.

Exceptions

Type	Condition
ArgumentNullException	source is null
ArgumentNullException	predicate is null
ArgumentNullException	resultSelector is null