Group-by-in-linq

using System;
using System.Linq;
using System.Collections.Generic;

class Person
{ 
    public int PersonId; 
    public string car  ; 
}

class Result
{ 
   public int PersonId;
   public List<string> Cars; 
}

public class Program
{
    public static void Main()
    {
        List<Person> persons = new List<Person>()
        {
            new Person { PersonId = 1, car = "Ferrari" },
            new Person { PersonId = 1, car = "BMW" },
            new Person { PersonId = 2, car = "Audi"}
        };

        //With Query Syntax

        List<Result> results1 = (
            from p in persons
            group p by p.PersonId into g
            select new Result()
                {
                    PersonId = g.Key, 
                    Cars = g.Select(c => c.car).ToList()
                }
            ).ToList();

        foreach (Result item in results1)
        {
            Console.WriteLine(item.PersonId);
            foreach(string car in item.Cars)
            {
                Console.WriteLine(car);
            }
        }

        Console.WriteLine("-----------");

        //Method Syntax

        List<Result> results2 = persons
            .GroupBy(p => p.PersonId, 
                     (k, c) => new Result()
                             {
                                 PersonId = k,
                                 Cars = c.Select(cs => cs.car).ToList()
                             }
                    ).ToList();

        foreach (Result item in results2)
        {
            Console.WriteLine(item.PersonId);
            foreach(string car in item.Cars)
            {
                Console.WriteLine(car);
            }
        }
    }
}

Source: stackoverflow.com

Similar codes

0 vote302 views2 answers
Relative path c#
C#
0 vote351 views1 answer
C# WPF Timer
C#
21 votes325 views3 answers
How to detect collision in unity
C#Unity
0 vote285 views1 answer
C# catch multiple exceptions at once
C#
94 votes290 views6 answers
How to convert string to int in c#
C#
17 votes211 views1 answer
Check if dictionary contains value c#
C#
0 vote302 views1 answer
Unity check if current scene is being unloaded
C#
0 vote288 views6 answers
For
C#
-1 vote330 views1 answer
Access audio source from gameobject unity
C#Unity
9 votes261 views1 answer
Camera follow
C#