MoreEnumerable.FallbackIfEmpty(T) Method (IEnumerable(T), T)

MoreEnumerableFallbackIfEmptyT Method (IEnumerableT, T)

Returns the elements of the specified sequence or the specified value in a singleton collection if the sequence is empty.

Namespace: MoreLinq
Assembly: MoreLinq (in MoreLinq.dll) Version: 2.2.0

Syntax

public static IEnumerable<T> FallbackIfEmpty<T>(
	this IEnumerable<T> source,
	T fallback
)

<ExtensionAttribute>
Public Shared Function FallbackIfEmpty(Of T) ( 
	source As IEnumerable(Of T),
	fallback As T
) As IEnumerable(Of T)

public:
[ExtensionAttribute]
generic<typename T>
static IEnumerable<T>^ FallbackIfEmpty(
	IEnumerable<T>^ source, 
	T fallback
)

[<ExtensionAttribute>]
static member FallbackIfEmpty : 
        source : IEnumerable<'T> * 
        fallback : 'T -> IEnumerable<'T>

source: Type: System.Collections.GenericIEnumerableT
The source sequence.
fallback: Type: T
The value to return in a singleton collection if source is empty.

Type: IEnumerableT
An IEnumerableT that contains fallback if source is empty; otherwise, source.

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerableT. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

Examples

var numbers = { 123, 456, 789 };
var result = numbers.Where(x => x == 100).FallbackIfEmpty(-1).Single();

The result variable will contain -1.