How to convert list item to multidimensional array in c#?

Question

I have a single list of data like

List 0 index Contains : BlockId = 438001,DistrictId = 438,TownId = 0,UserId = 1077
UserTypeId = 4,VillageId = 238047,ZoneId = 1018
List 1 index contains : BlockId = 438001,DistrictId = 438,TownId = 0,UserId = 1077,UserTypeId = 4,VillageId = 238048,ZoneId = 1018
List 2 index contains : BlockId = 438002,DistrictId = 438,TownId = 0,UserId = 1077,UserTypeId = 4,VillageId = 238138,ZoneId = 1018

And now I want to create a multidimensional array according to that like public List<int>[][] arrayList{get;set;}

I need to convert list data to multidimensional array list like

[0]
[0] -> Count 1 -> 438001  --> Showing blockId
[1]-> Count 3 -> 238047,238048 --> showing villageId


[1]
[0]->count 1 -> 438002
[1]->count 2 -> 238138
[2]->count 3-> 0 --> showing townId



var data = user.getUserRolebyUserId(userId);
var blkList = data.GroupBy(x => x.BlockId);
List<int>[][] lst;
foreach (var item in data.GroupBy(x => x.BlockId))
{
    List<int>[][] array = [item.Key,item.Select(x => x.VillageId).ToList(), item.Select(q => q.TownId)];
}

I am trying to applying this but it's showing me error for Invalid Expression. So How can I convert list into multidimensional array ?

List<int>[][] this is not a multidimensional array, its a jagged array of List<int> — TheGeneral
– TheGeneral, Commented Apr 30, 2019 at 9:40
Aside from what TheGeneral said, ... = [something, something, something]; is not even valid C# syntax. I guess it perhaps indicates the need to spend some more time with C# tutorials covering the basics of how to create, initialize and use arrays and collections.... — user2819245
– user2819245, Commented Apr 30, 2019 at 9:45
I am trying to List<int>[][] array = new int[][] {item.Key, item1.VillageId, item1.TownId }; but it's also not converting it. — Ankit
– Ankit, Commented Apr 30, 2019 at 9:49
You declare a variable of type List<int>[][] but then try to create and assign a int[][] instance to it. (An int[][] is not even remotely the same as nor is it convertible to List<int>[][]) What? That doesn't make a lick of sense... — user2819245
– user2819245, Commented Apr 30, 2019 at 9:51

jdweng · Accepted Answer · 2019-04-30 11:16:04Z

1

Use a Dictionary :

   class Program
    {
        static void Main(string[] args)
        {
            List<Location> locations = new List<Location>() {
                new Location() { BlockId = 438001,DistrictId = 438,TownId = 0,UserId = 1077, UserTypeId = 4,VillageId = 238047,ZoneId = 1018 },
                new Location() { BlockId = 438001,DistrictId = 438,TownId = 0,UserId = 1077,UserTypeId = 4,VillageId = 238048,ZoneId = 1018},
                new Location() { BlockId = 438002,DistrictId = 438,TownId = 0,UserId = 1077,UserTypeId = 4,VillageId = 238138,ZoneId = 1018 }
            };

            Dictionary<int, List<int>> dict = locations
                .GroupBy(x => x.BlockId, y => y.Items)
                .ToDictionary(x => x.Key, y => y.FirstOrDefault());

        }
    }
    public class Location
    {
        public int BlockId { get; set; }
        public int DistrictId { get; set; }
        public int TownId { get; set; }
        public int UserId { get; set; }
        public int UserTypeId { get; set; }
        public int VillageId { get; set; }
        public int ZoneId { get; set; }

        public List<int> Items {
            get { return new List<int> { BlockId, DistrictId, TownId, UserId, UserTypeId, VillageId, ZoneId }; }
            set {;}
        }
    }

edited Apr 30, 2019 at 11:16

answered Apr 30, 2019 at 9:55

jdweng

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3 Comments

Ankit Over a year ago

Dictionary is new for me. can I able to convert this Dictionary into List<int>[][] ?

jdweng Over a year ago

You really have three levels of arrays (not two) since you are using a GroupBy. A GroupBy creates a two dimensional array [key][List]. In your case the List is an array of attributes (BlockId, DistrictId, TownId, ...). So do you really want to remove the attribute names like "BlockId" when you say List<int>[][]?

Ankit Over a year ago

Yes actually I need List of Int which will contains two array in which first one will contains villageId and second one will contains townId. I am searching for convert dictionary to List<int>[][] but almost are using only int[][].

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