[LINQ Operators] Last

The “Last” operator returns the last element of a sequence or throws an exception 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. “Last” operator

  • NonDeferred operator
  • Purpose: Element

 

3. Prototypes

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

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

The “Last()” operator returns the last element in a sequence. In the second syntax, you can provide the condition and it works like you are using the “Where” operator. The “Last()” operator throws an exception when there’s no element to return. Therefore, you need to use this operator in a “try/catch” block or use the “LastOrDefault()” operator instead.

 

4. Example 1 (Standard Operator)

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

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

try
{
  Employee emp1 =
    emps.Where(e => e.Name.Contains("NoName")).Last();
}
catch
{
  Console.WriteLine("Cannot find any employee");
}

 

5. Example 2 (Query Expression)

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

 

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

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

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

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

This example is the same as the previous one but it is simpler.

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