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.
Assembly: System.Core (in System.Core.dll)
public static TSource LastOrDefault<TSource>( this IEnumerable<TSource> source, Func<TSource, bool> predicate )
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: TSourcedefault(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.
Type Parameters
- TSource
The type of the elements of source.
| Exception | Condition |
|---|---|
| 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>. */
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1