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Enumerable.LastOrDefault<TSource> Method (IEnumerable<TSource>, Func<TSource, Boolean>)

Returns the last element of a sequence that satisfies a condition or a default value if no such element is found.

Namespace:  System.Linq
Assemblies:   System.Linq (in System.Linq.dll)
  System.Core (in System.Core.dll)

public static TSource LastOrDefault<TSource>(
	this IEnumerable<TSource> source,
	Func<TSource, bool> predicate
)

Type Parameters

TSource

The type of the elements of source.

Parameters

source
Type: System.Collections.Generic.IEnumerable<TSource>

An IEnumerable<T> to return an element from.

predicate
Type: System.Func<TSource, Boolean>

A function to test each element for a condition.

Return Value

Type: TSource
default(TSource) if the sequence is empty or if no elements pass the test in the predicate function; otherwise, the last element that passes the test in the predicate function.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<TSource>. 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).

ExceptionCondition
ArgumentNullException

source or predicate is null.

The default value for reference and nullable types is null.

The following code example demonstrates how to use LastOrDefault<TSource>(IEnumerable<TSource>, Func<TSource, Boolean>) by passing in a predicate. In the second call to the method, there is no element in the sequence that satisfies the condition.

            double[] numbers = { 49.6, 52.3, 51.0, 49.4, 50.2, 48.3 };

            double last50 = numbers.LastOrDefault(n => Math.Round(n) == 50.0);

            Console.WriteLine("The last number that rounds to 50 is {0}.", last50);

            double last40 = numbers.LastOrDefault(n => Math.Round(n) == 40.0);

            Console.WriteLine(
                "The last number that rounds to 40 is {0}.",
                last40 == 0.0 ? "<DOES NOT EXIST>" : last40.ToString());

            /*
             This code produces the following output:

             The last number that rounds to 50 is 50.2.
             The last number that rounds to 40 is <DOES NOT EXIST>.
            */

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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