using System;

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

  public static void Main()

  {

    Container data = new();

    var measures = data.Measurement;

    Console.WriteLine((measures.GetType()));

    Console.WriteLine(measures);

    Console.WriteLine(measures.Keys.Count());

    Console.WriteLine(measures is null);

  }

}

​

public class Container

{

  public Guid Id { get; init; }

  public virtual IEnumerable<Measure> Measures { get; init; }

  public Dictionary<string, Measure[]> Measurement 

    => (Measures ?? Array.Empty<Measure>())

      .GroupBy(a => a.Type).ToDictionary(a => a.Key, a => a.ToArray());

}

​

public class Measure

{

  public string Name { get; set; }

  public string Type { get; set; }

}