Question

I have a data source, containing the following columns:

ID | Tile | Score | Type

I have several rows in this data source, but of interest is the “Type” column that contains a type definition, each row belongs to, something like:

1 | Apple  | 12 | Pipped

2 | Banana | 34 | Flesh

3 | Kiwi   | 32 | Flesh

4 | Orange | -1 | Pipped

5 | Grapes | 3  | Pipped

6 | Potato | 5  | Skinned

I need to pull this information into a collection, or a KeyValuePair<string, List<Data>> but cannot find an efficient way to do this.

I’m currently using LINQ to pull a collection for each of the types (enumerator):

var pipped = (from p in dataSource where p.Type != null && p.Type.Equals(enum.Pipped) select p).ToList();

var flesh = (from p in dataSource where p.Type != null && p.Type.Equals(enum.Flesh) select p).ToList();

var skinned = (from p in dataSource where p.Type != null && p.Type.Equest(enum.Skinned) select p).ToList();

SortedDictionary<string, List<dataSource>> items = new SortedDictionary<string, List<dataSource>>();

items.Add("Pipped", pipped);
items.Add("Skinned", skinned);
items.Add("Flesh", flesh);

There must be a more efficient way to do this?

Answer 1

Looks like you want to use a GroupBy with a ToDictionary like this:

var dictionary = (from x in datasource
                  where x.Type != null
                  group x by x.Type into x
                  select x).ToDictionary(x => x.Key, x => x.ToList());

Or if you want to use method syntax:

var dictionary = datasource.Where(x => x.Type != null)
                           .GroupBy(x => x.Type)
                           .ToDictionary(x => x.Key, x => x.ToList());