/** Linq - Where and FirstOrDefault (For Collection e.g. List, Array, etc) **/

​

using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var loopingList = new List<string>

        {

            "1",

            "12",

            "123"

        };

        var collectionLessThan3Characters = new List<string>();

        foreach (var item in loopingList)

        {

            if (item.Length < 3)

            {

                collectionLessThan3Characters.Add(item);

            }

        }

        // collectionLessThan3Characters.Count.ShouldEqual(2);

        Console.WriteLine("First collection Count: " + collectionLessThan3Characters.Count);

        var collectionLessThan3 = loopingList.Where(item => item.Length < 3).ToList();

        // collectionLessThan3.Count.ShouldEqual(2);

        Console.WriteLine("Second collection Count: " + collectionLessThan3.Count);

        //Method 1

        var itemLessThan3ButContain2 = string.Empty;

                foreach (var item in collectionLessThan3Characters) {

            if (item.Contains("2")) {

                itemLessThan3ButContain2 = item;

            }

        }

        Console.WriteLine("Item less than 3 length but contain 2 first method: " + itemLessThan3ButContain2);

        //Method 2

        itemLessThan3ButContain2 = string.Empty;

        itemLessThan3ButContain2 = collectionLessThan3Characters.FirstOrDefault(item => item.Contains("2"));

        Console.WriteLine("Item less than 3 length but contain 2 second method: " + itemLessThan3ButContain2);

    }

}

​

​