ElementAt

In this chapter you will learn:

How to use ElementAt operator
ElementAt vs ElementAtOrDefault
Use ElementAt to print the fourth number less that 5 in an integer array

Get to know ElementAt operator

using System;/* j a va 2  s. c  o m*/
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);
   }
}

ElementAt vs ElementAtOrDefault

ElementAt picks the nth element from the sequence:

using System;//j a  va 2s.  c o m
using System.Collections;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main()
    {
        int[] numbers = { 1, 2, 3, 4, 5 };
        int third = numbers.ElementAt(2);
        int tenthError = numbers.ElementAt(9);  // Exception 
        int tenth = numbers.ElementAtOrDefault(9);  // 0
        Console.WriteLine(third);
        Console.WriteLine(tenth);
    }
}

The output:

Get element after select

using System;//from  j ava2s  .  co m
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);
    }
}

Next chapter...

What you will learn in the next chapter:

How to use ElementAtOrDefault opeator