[LINQ Operators] LastOrDefault

The “LastOrDefault” operator returns the last element of a sequence, or a default value if no element is found. You can provide the predicate delegate instead of using the “Where” operator.

 

1. Sample Data Object

To test examples, you need to include the <data classes> in your project.

 

2. “LastOrDefault” operator

  • NonDeferred operator
  • Purpose: Element

 

3. Prototypes

public static T LastOrDefault<T>(
  this IEnumerable<T> source)

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

The “LastOrDefault()” operator returns the last element in a sequence just like the “Last()” operator. The main difference is that the “LastOrDefault()” returns a default value if the sequence is empty or there’s no matching element.

 

4. Example 1 (Standard Operator)

IEnumerable<Employee> emps = Employee.GetEmployees();

Employee emp =
  emps.Where(e => e.Name.Contains("Smith")).LastOrDefault();
Console.WriteLine($"Last Matching Employee: {emp.Name}"); // Mark Smith

Employee emp1 =
  emps.Where(e => e.Name.Contains("NoName")).LastOrDefault();
if(emp1 == null)
{
  Console.WriteLine("Cannot find any employee");
}

 

5. Example 2 (Query Expression)

There’s no corresponding query expression for the “LastOrDefault()” operator.

 

6. Example 3 (Standard Operator) – with a condition

IEnumerable<Employee> emps = Employee.GetEmployees();

Employee emp =
  emps.LastOrDefault(e => e.Name.Contains("Smith"));

Console.WriteLine($"Last Matching Employee: {emp.Name}"); // Mark Smith

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