using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        double[] numbers1 = { 2.0, 2.0, 2.1, 2.2, 2.3, 2.3, 2.4, 2.5 };

        double[] numbers2 = { 2.2 };

​

        IEnumerable<double> onlyInFirstSet = numbers1.Except(numbers2);

        System.Console.WriteLine($"{nameof(onlyInFirstSet)} count: {onlyInFirstSet.Count()}");

        IEnumerable<double> onlyInSecondSet = numbers2.Except(numbers1);

        System.Console.WriteLine($"{nameof(onlyInSecondSet)} count: {onlyInSecondSet.Count()}");

    }

}