CODEWITHSUNDEEP
c#linq
Idrees
Idrees

Reputation: 833

How to remove from the list the items that have parents in the same list

I have a List<Item>.

How can I remove items that have parents in the same list using LINQ?

If it is possible I prefer method chain expression.

Item definition:

public class Item {
        public int Id { get; set; }
        public int ParentId { get; set; }
    }

Upvotes: 1

Views: 1399

Answers (2)

Hossein Narimani Rad
Hossein Narimani Rad

Reputation: 32481

This may help

List<Item> items = new List<Item>();
items.Add(new Item() { Id = 1, ParentId = 2 });
items.Add(new Item() { Id = 2, ParentId = 0 });
items.Add(new Item() { Id = 3, ParentId = 0 });
items.Add(new Item() { Id = 4, ParentId = 1 });
items.Add(new Item() { Id = 5, ParentId = 1 });
items.Add(new Item() { Id = 6, ParentId = 4 });
items.Add(new Item() { Id = 7, ParentId = 4 });
items.Add(new Item() { Id = 8, ParentId = 4 });
items.Add(new Item() { Id = 9, ParentId = 4 });
items.Add(new Item() { Id = 10, ParentId = 4 });
items.Add(new Item() { Id = 11, ParentId = 4 });

var shouldBeRemove =
    (from i in items
     where items.Any(input => input.Id == i.ParentId)
     select i).ToList();

items.RemoveAll(input => shouldBeRemove.Contains(input));

//Those who remain
//item with Id = 2
//item with Id = 3

Upvotes: 3

James
James

Reputation: 9975

var Children = List.Where(child => List.Any(parent => parent.Id == child.ParentID)).ToList();
List.RemoveAll(child => Children.Contains(child));

Upvotes: 3

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