C# Linq Order a list with a reference list

Question

I have two lists and I need to sort a list with another list.

var orderList = new List<long>() {4, 55, 34};
var itemList = new List<Branch>() { {Id=55, Name="X"},  {Id=34, Name="Y"}, {Id=4, Name="Z"} };

How can I order second list namely itemList according to first one orderList ?

Is there any linq short way?

Update:

orderList will always have all expected Id branch contained itemList.

What should happen to items from `itemList` that doesn't exist in `orderList` ? How should they be ordered in this scenario? — Fabjan, Jun 12 '18 at 08:05
@Fabjan, there is not such a case in my problem. I get itemList according to orderList. If you have a solution to get itemList ordered by orderList then it is also accepted — ahmet, Jun 12 '18 at 08:06
@Fabjan I didn't see the comment of the OP so I updated his question. — CodeNotFound, Jun 12 '18 at 08:20

score 4 · Accepted Answer · answered Jun 12 '18 at 08:07

4

You could use LINQ and order the items by their index in other array:

var orderedItemList = itemList.OrderBy(x => orderList.IndexOf(x.Id)).ToList();

answered Jun 12 '18 at 08:07

Fabjan

score 4 · Answer 2 · answered Jun 12 '18 at 08:12

4

you can perform below linq to solve your issue:

 List<Branch> sortedProducts = new List<Branch>();

 orderList.ForEach(x => sortedProducts.Add(itemList.FirstOrDefault(ele => ele.Id == x)));

Note:- here only those element will be added whose index is present in the orderList.

answered Jun 12 '18 at 08:12

Lucifer

1

Thanks for marking as duplicated. I couldn't find it, you did. – ahmet Jun 12 '18 at 08:31

score 2 · Answer 3 · answered Jun 12 '18 at 08:07

2

You can do the following:

itemList = itemList.OrderBy(d => orderList.IndexOf(d.Id)).ToList();

answered Jun 12 '18 at 08:07

Raviraj Palvankar

score 2 · Answer 4 · answered Jun 12 '18 at 08:07

2

you can order by the index of the Id in the orderList:

var result = itemList.OrderBy(e => orderList.IndexOf(e.Id)).ToList();

answered Jun 12 '18 at 08:07

Ousmane D.

4 Answers4