Enumerable.LastOrDefault Method

Definition

Returns the last element of a sequence, or a default value if no element is found.

Overloads

LastOrDefault<TSource>(IEnumerable<TSource>)

Returns the last element of a sequence, or a default value if the sequence contains no elements.

LastOrDefault<TSource>(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.

LastOrDefault<TSource>(IEnumerable<TSource>, TSource)

Returns the last element of a sequence, or a specified default value if the sequence contains no elements.

LastOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>, TSource)

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

LastOrDefault<TSource>(IEnumerable<TSource>)

Source:
Last.cs
Source:
Last.cs
Source:
Last.cs

Returns the last element of a sequence, or a default value if the sequence contains no elements.

C#
public static TSource LastOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source);
C#
public static TSource? LastOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source);

Type Parameters

TSource

The type of the elements of source.

Parameters

source
IEnumerable<TSource>

An IEnumerable<T> to return the last element of.

Returns

TSource

default(TSource) if the source sequence is empty; otherwise, the last element in the IEnumerable<T>.

Exceptions

source is null.

Examples

The following code example demonstrates how to use LastOrDefault<TSource>(IEnumerable<TSource>) on an empty array.

C#
string[] fruits = { };
string last = fruits.LastOrDefault();
Console.WriteLine(
    String.IsNullOrEmpty(last) ? "<string is null or empty>" : last);

/*
 This code produces the following output:

 <string is null or empty>
*/

Sometimes the value of default(TSource) is not the default value that you want to use if the collection contains no elements. Instead of checking the result for the unwanted default value and then changing it if necessary, you can use the DefaultIfEmpty<TSource>(IEnumerable<TSource>, TSource) method to specify the default value that you want to use if the collection is empty. Then, call Last<TSource>(IEnumerable<TSource>) to obtain the last element. The following code example uses both techniques to obtain a default value of 1 if a collection of numeric days of the month is empty. Because the default value for an integer is 0, which does not correspond to any day of the month, the default value must be specified as 1 instead. The first result variable is checked for the unwanted default value after the query has finished executing. The second result variable is obtained by using DefaultIfEmpty<TSource>(IEnumerable<TSource>, TSource) to specify a default value of 1.

C#
List<int> daysOfMonth = new List<int> { };

// Setting the default value to 1 after the query.
int lastDay1 = daysOfMonth.LastOrDefault();
if (lastDay1 == 0)
{
    lastDay1 = 1;
}
Console.WriteLine("The value of the lastDay1 variable is {0}", lastDay1);

// Setting the default value to 1 by using DefaultIfEmpty() in the query.
int lastDay2 = daysOfMonth.DefaultIfEmpty(1).Last();
Console.WriteLine("The value of the lastDay2 variable is {0}", lastDay2);

/*
 This code produces the following output:

 The value of the lastDay1 variable is 1
 The value of the lastDay2 variable is 1
*/

Remarks

The default value for reference and nullable types is null.

The LastOrDefault method does not provide a way to specify a default value. If you want to specify a default value other than default(TSource), use the DefaultIfEmpty<TSource>(IEnumerable<TSource>, TSource) method as described in the Example section.

Applies to

.NET 9 and other versions
Product Versions
.NET Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 1.0, 1.1, 1.2, 1.3, 1.4, 1.6, 2.0, 2.1
UWP 10.0

LastOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)

Source:
Last.cs
Source:
Last.cs
Source:
Last.cs

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

C#
public static TSource LastOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,bool> predicate);
C#
public static TSource? LastOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,bool> predicate);

Type Parameters

TSource

The type of the elements of source.

Parameters

source
IEnumerable<TSource>

An IEnumerable<T> to return an element from.

predicate
Func<TSource,Boolean>

A function to test each element for a condition.

Returns

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.

Exceptions

source or predicate is null.

Examples

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.

C#
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>.
*/

Remarks

The default value for reference and nullable types is null.

Applies to

.NET 9 and other versions
Product Versions
.NET Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 1.0, 1.1, 1.2, 1.3, 1.4, 1.6, 2.0, 2.1
UWP 10.0

LastOrDefault<TSource>(IEnumerable<TSource>, TSource)

Source:
Last.cs
Source:
Last.cs
Source:
Last.cs

Returns the last element of a sequence, or a specified default value if the sequence contains no elements.

C#
public static TSource LastOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, TSource defaultValue);

Type Parameters

TSource

The type of the elements of source.

Parameters

source
IEnumerable<TSource>

An IEnumerable<T> to return the last element of.

defaultValue
TSource

The default value to return if the sequence is empty.

Returns

TSource

defaultValue if the source sequence is empty; otherwise, the last element in the IEnumerable<T>.

Exceptions

source is null.

Applies to

.NET 9 and other versions
Product Versions
.NET 6, 7, 8, 9

LastOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>, TSource)

Source:
Last.cs
Source:
Last.cs
Source:
Last.cs

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

C#
public static TSource LastOrDefault<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,bool> predicate, TSource defaultValue);

Type Parameters

TSource

The type of the elements of source.

Parameters

source
IEnumerable<TSource>

An IEnumerable<T> to return an element from.

predicate
Func<TSource,Boolean>

A function to test each element for a condition.

defaultValue
TSource

The default value to return if the sequence is empty.

Returns

TSource

defaultValue 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.

Exceptions

source or predicate is null.

Applies to

.NET 9 and other versions
Product Versions
.NET 6, 7, 8, 9