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

7 votes342 views2 answers
Unity float from another script
C#
4 votes327 views1 answer
Covert char[] to string C#
C#
0 vote298 views2 answers
How to trim path in C#
C#
16 votes263 views10 answers
How to code
C#
0 vote284 views1 answer
Linq query to fetch parent child data from same table in c#
C#
0 vote322 views2 answers
Append multi lines to file linux
C#
2 votes305 views1 answer
How to set progress openedge driver name for odbc connection c#
C#
0 vote304 views1 answer
Death transition unity 2d
C#
0 vote315 views1 answer
Make 2D object move at constant speed unity
C#
1 vote307 views1 answer
How to convert from hexadecimal to binary in c#
C#