.NET 9 Index in LINQ

 

About

Index is one of feature introduced in .NET LINQ. By using this method, we can easily extract implicit index of IEnumerable.

The other .NET 9 LINQ features are as follows.

.NET 9 CountBy in LINQ

.NET 9 AggregateBy in LINQ

The Index method returns index and index of an item in following format.

Format: IEnumerable<(int Index, TSource Item)>

Scenario

Lets consider to display employee name in list and their respective order.

Employee class

public class Employee

{

    public int Id { get; set; }

    public string Name { get; set; }

}

Setup Employee List with Sample Data

  var employees = new List<Employee> {

  new Employee(){ Id = 11, Name = "Ram" },

  new Employee(){ Id = 12, Name = "Bheem" },

  new Employee(){Id = 13, Name = "Lakshman"},

  new Employee(){Id = 14, Name = "Hanu"},

  new Employee(){Id = 15, Name = "Dev"},

  new Employee(){Id = 16, Name = "Nandan"},

  new Employee(){Id = 17, Name = "Krish"},

  new Employee(){Id = 18, Name = "Hash"},

};

  foreach ((int index, Employee emp) in employees.Index())

  {

      Console.WriteLine($"Index: {index}, Employee Name: {emp.Name}");

  }

Screenshots

The following code and output screenshots gives easy understanding and for your implementation.

Code

Output

Summary

This post explored about Index feature in LINQ introduced in .NET9.

Thanks for reading this and stay tuned for more articles.