ParallelEnumerable.First Method

Definition

Returns the first element of a parallel sequence.

Overloads

First<TSource>(ParallelQuery<TSource>)

Returns the first element of a parallel sequence.

First<TSource>(ParallelQuery<TSource>, Func<TSource,Boolean>)

Returns the first element in a parallel sequence that satisfies a specified condition.

First<TSource>(ParallelQuery<TSource>)

Returns the first element of a parallel sequence.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static TSource First(System::Linq::ParallelQuery<TSource> ^ source);
public static TSource First<TSource> (this System.Linq.ParallelQuery<TSource> source);
static member First : System.Linq.ParallelQuery<'Source> -> 'Source
<Extension()>
Public Function First(Of TSource) (source As ParallelQuery(Of TSource)) As TSource

Type Parameters

TSource

The type of the elements of source.

Parameters

source
ParallelQuery<TSource>

The sequence to return the first element of.

Returns

TSource

The first element in the specified sequence.

Exceptions

The query was canceled with the token passed in through WithCancellation.

source is a null reference (Nothing in Visual Basic).

One or more exceptions occurred during the evaluation of the query.

source contains no elements.

Remarks

If the query is not ordered, then the first element is non-deterministic. For more information, see Order Preservation in PLINQ.

See also

First<TSource>(ParallelQuery<TSource>, Func<TSource,Boolean>)

Returns the first element in a parallel sequence that satisfies a specified condition.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static TSource First(System::Linq::ParallelQuery<TSource> ^ source, Func<TSource, bool> ^ predicate);
public static TSource First<TSource> (this System.Linq.ParallelQuery<TSource> source, Func<TSource,bool> predicate);
static member First : System.Linq.ParallelQuery<'Source> * Func<'Source, bool> -> 'Source
<Extension()>
Public Function First(Of TSource) (source As ParallelQuery(Of TSource), predicate As Func(Of TSource, Boolean)) As TSource

Type Parameters

TSource

The type of the elements of source.

Parameters

source
ParallelQuery<TSource>

The sequence to return an element from.

predicate
Func<TSource,Boolean>

A function to test each element for a condition.

Returns

TSource

The first element in the sequence that passes the test in the specified predicate function.

Exceptions

The query was canceled with the token passed in through WithCancellation.

source or predicate is a null reference (Nothing in Visual Basic).

One or more exceptions occurred during the evaluation of the query.

No element in source satisfies the condition in predicate.

Remarks

If the query is not ordered, then the first element is non-deterministic. For more information, see Order Preservation in PLINQ.

See also

Applies to