Csharp/C Sharp/LINQ/ElementAt

Calling the ElementAt Operator

 
using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class Employee {
    public int id;
    public string firstName;
    public string lastName;
    public static ArrayList GetEmployeesArrayList() {
        ArrayList al = new ArrayList();
        al.Add(new Employee { id = 1, firstName = "J", lastName = "R" });
        al.Add(new Employee { id = 2, firstName = "W", lastName = "G" });
        al.Add(new Employee { id = 3, firstName = "A", lastName = "H" });
        al.Add(new Employee { id = 4, firstName = "D", lastName = "L" });
        al.Add(new Employee { id = 101, firstName = "K", lastName = "F" });
        return (al);
    }
    public static Employee[] GetEmployeesArray() {
        return ((Employee[])GetEmployeesArrayList().ToArray(typeof(Employee)));
    }
}
public class MainClass {
    public static void Main() {
        Employee emp = Employee.GetEmployeesArray().ElementAt(3);
        Console.WriteLine("{0} {1}", emp.firstName, emp.lastName);
    }
}

The element operators extract one element from the input sequence

 
//First, Last, Single, and ElementAt
using System;
using System.Collections.Generic;
using System.Linq;
public class MainClass {
    public static void Main() {
        int[] numbers = { 10, 9, 8, 7, 6 };
        int firstNumber = numbers.First();    
        int lastNumber = numbers.Last();      
        int secondNumber = numbers.ElementAt(1);
        int lowestNumber = numbers.OrderBy(n => n).First();
    }
}

use ElementAt

 
using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Linq;
public class MainClass{
   public static void Main(){
            int[] numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9};
            var query = numbers.ElementAt(4);
            Console.Write(query);
   }
}

Use ElementAt to print the fourth number less that 5 in an integer array

 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
public class MainClass {
    public static void Main() {
        int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
        int fourthLowNum = (
            from n in numbers
            where n < 5
            select n)
            .ElementAt(3); // 3 because sequences use 0-based indexing
        Console.WriteLine("Fourth number < 5: {0}", fourthLowNum);
    }
}