2012-02-23 07:49:27 8 Comments
MyClass
consists of ID
ParentID
and List<MyClass>
as Children
I have list of MyClass
like this
ID ParentID
1 0
2 7
3 1
4 5
5 1
6 2
7 1
8 6
9 0
10 9
Output (Hierarchical list) as List<MyClass>
1 __ 3
|__ 5__ 4
|__ 7__ 2__ 6__ 8
|__ 11
9 __10
What is the simplest way to achieve this in linq?
P.S.: ParentID
not sorted
Edit:
My try:
class MyClass
{
public int ID;
public int ParentID;
public List<MyClass> Children = new List<MyClass>();
public MyClass(int id, int parent_id)
{
ID = id;
ParentID = parent_id;
}
}
initialize sample data and try to reach hierarchical data
List<MyClass> items = new List<MyClass>()
{
new MyClass(1, 0),
new MyClass(2, 7),
new MyClass(3, 1),
new MyClass(4, 5),
new MyClass(5, 1),
new MyClass(6, 2),
new MyClass(7,1),
new MyClass(8, 6),
new MyClass(9, 0),
new MyClass(10, 9),
new MyClass(11, 7),
};
Dictionary<int, MyClass> dic = items.ToDictionary(ee => ee.ID);
foreach (var c in items)
if (dic.ContainsKey(c.ParentID))
dic[c.ParentID].Children.Add(c);
as you can see, lots of items I don't want still in the dictionary
Related Questions
Sponsored Content
46 Answered Questions
[SOLVED] How to make a flat list out of list of lists?
- 2009-06-04 20:30:05
- Emma
- 1863356 View
- 2987 Score
- 46 Answer
- Tags: python list multidimensional-array flatten
62 Answered Questions
7 Answered Questions
26 Answered Questions
[SOLVED] How do I concatenate two lists in Python?
- 2009-11-12 07:04:09
- y2k
- 2226473 View
- 2274 Score
- 26 Answer
- Tags: python list concatenation
28 Answered Questions
16 Answered Questions
11 Answered Questions
29 Answered Questions
20 Answered Questions
[SOLVED] What is the difference between Python's list methods append and extend?
- 2008-10-31 05:55:36
- Claudiu
- 2855941 View
- 3119 Score
- 20 Answer
- Tags: python list data-structures append extend
3 comments
@JLRishe 2013-01-23 06:27:06
Recursion is not necessary here if you build the parent-child relationships before filtering. Since the members of the list remain the same objects, as long as you associate each member of the list with its immediate children, all of the necessary relationships will be built.
This can be done in two lines:
@Sarin 2013-04-04 22:05:07
I did not think of that. You're correct. Creating the hierarchy does not require recursion, only traversing does.
@DiVan 2013-06-04 05:48:33
Traversing does not too. :)
@Three Value Logic 2014-12-10 13:37:11
Just used this for a similar project. Beautiful solution and efficient too.
@arjthakur 2014-04-01 10:05:11
I have required such functionality and compare both methods and find method 2nd is faster than 1st :), right now in my database cards or records are limited but 1st method taking 4 times more time to complete.
may be this can help for those who are conscious about time.
1 method
method 2
@Sarin 2012-02-25 01:48:57
For hierarchical data, you need recursion - a foreach loop won't suffice.
items
is the same list you use. Notice how theSetChildren
method is called within itself. This is what constructs the hierarchy.@Andrew Hanlon 2014-09-28 13:27:49
This is less performant than the OPs original code. The dictionary method is far superior.
@Shailesh 2016-05-31 11:40:16
Nice user347805, Its working for me
@Stfvns 2017-07-20 09:17:42
@user347805 @RamiShareef I want the output list add like print
|__|__11
if that is a child. and if that is a parent just print1
. help please. thank@kunal verma 2019-09-17 07:55:27
@sarin it ends up in infinite loop . what's the break condition