Using Linq to Group a List of Objects into a New Grouped List of List of Objects

Using Linq to group a list of objects into a new grouped list of list of objects

var groupedCustomerList = userList
    .GroupBy(u => u.GroupID)
    .Select(grp => grp.ToList())
    .ToList();

Using Linq to group a list of objects into a new grouped list of list of objects with 4 objects in each group

May be this could Help.

Source:

public class Job
{
    public int JobID { get; set; }

    public static Job[] GetJobs()
    {
        var jobList = new[] {
        new Job { JobID = 1 },
        new Job { JobID = 2},
        new Job { JobID = 3},
        new Job { JobID = 4},
        new Job { JobID = 5},
        new Job { JobID = 6},
        new Job { JobID = 7},
        new Job { JobID = 8},
        new Job { JobID = 9},
        new Job { JobID = 10}
    };
    return jobList;
    }

    public override string ToString()
    {
        return $"Job {{ JobID={JobID} }}";            
    }
}

Group Query Using Linq:

       //Data Source
        var source = Job.GetJobs();
  
        //Query Creation
        var query = from index in Enumerable.Range(0, source.Length) 
                    group source[index] by index / 4;

        //Query Execution
        foreach (var item in query)
        {
            Console.WriteLine($"Group : {item.Key}");               
            item.ToList().ForEach(it => Console.WriteLine(it.ToString()));               
        }
       
        Console.ReadLine();

Expected Ouput:

Using Linq to group a list of objects that contains primitives data into a new grouped list of objects

You can just order type name by descending after Select, it'll give you the desired output - (string, integer, double, character) items

list.GroupBy(x => x.GetType())
    .OrderByDescending(g => g.Key.Name)
    .Select(grp => grp.ToList())
    .ToList()
    .ForEach(group => group.ForEach(Console.WriteLine));

Another option is order by IsPrimitive property OrderBy(g => g.Key.IsPrimitive), for your particular data it also gives the desired output

C# LINQ GroupBy to convert a List to a group with one property as List of values

After GroupBy, use ToDictionary:

source.GroupBy(x => x.Name)
      .ToDictionary(x => x.Key, x => x.Select(e => e.Value).ToList());

This yields a Dictionary<string, List<string>> where the keys are the names and the values are lists made up of projecting each element to a string under that specific group.

I assume that Value is a string for example purposes only but in reality, it doesn't really matter as the solution remains the same.

LINQ group data into a list of objects containing a list + selecting specific original data

Here is how you can write it :

return db.persondatas
    //.Where(/* ... */)
    .GroupBy(x => x.name, (name, g) => new ListData
    {
        label = name,
        data = g.GroupBy(d => d.x, (x, data) => new Point
            {
                x = x,
                y = data.Sum(d => d.y)
            })
            .ToList()
    }).ToList();

LINQ groupby to List List object

I think you are looking this:

var data = Model.Where(x => x.Start.Date == DateTime.UtcNow.Date)
                .GroupBy(x => new { x.Start, x.Field2 })
                .Select(g=>g.ToList()).ToList();

Add a Select call to get a list per each group

Pass LINQ Group By Data Into New List Of Objects

For the property initializer to work you need a parameterless constructor and your fields should be properties to be accessible:

public class DataPoint
{
    [DataMember(Name = "y")]
    public Nullable<double> Y  { get; set; };

    [DataMember(Name = "label")]
    public string Label { get; set; }

    public DataPoint()
    {
    }

    public DataPoint(double y, string label)
    {
       Y = y;
       Label = label;
    }
}

and now your code should compile, alternatively use the constructor with parameters as someone suggested in comments.

C# - Lambda - grouping List data containing nested List objects

I usually do it like this

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

namespace ConsoleApplication4
{
    class Program
    {
        static void Main(string[] args)
        {
            List<dDepartment> depts = new List<dDepartment>();

            var results = depts
                .SelectMany(g => g.Rooms
                    .SelectMany(s => s.Elements.Select( e => new { 
                        deptId = g.DepartmentId, 
                        deptName = g.DepartmentName, 
                        roomId = s.RoomId, 
                        roomName = s.RoomName,
                        elementId = e.ElementId,
                        elementName = e.ElementName
                    })
                    )).GroupBy(g => new {g.deptId, g.roomId})
                    .ToList();

        }
    }
    public class dDepartment
    {
        public int DepartmentId { get; set; }
        public string DepartmentName { get; set; }
        public List<dRoom> Rooms { get; set; }
    }

    public class dRoom
    {
        public int RoomId { get; set; }
        public string RoomName { get; set; }
        public List<dElement> Elements { get; set; }
    }

    public class dElement
    {
        public int ElementId { get; set; }
        public string ElementName { get; set; }
        public List<dAction> Actions { get; set; }
    }

    public class dAction
    {
        public int ActionId { get; set; }
        public string ActionName { get; set; }
        public int TimeNorm { get; set; }
        public int ElementCount { get; set; }

    }


}

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