How to implement a IEnumerator which support remove items in foreach

I write some code like this:

Code (CSharp):

1.         var list = new List<Int32>();
2.      
3.         for(Int32 i=0; i<10; i++)
4.             list.Add(i);
5.  
6.         IEnumerator it = list.GetEnumerator();
7.         while (it.MoveNext())     //<---------------Exception occured:
8.         {
9.             var item = (Int32)it.Current;
10.          
11.             if (item==2)
12.                 list.Remove(item);
13.          
14.             if (item==4)
15.                 list.Remove(item);
16.          
17.             if (item==6)
18.                 list.Remove(8);
19.         }
20.  
21.         foreach(var item in list)
22.             Debug.Log(item);

Exception occured:
Collection was modified; enumeration operation may not execute.

My question is:
Is it possible to rewrite IEnumerator to implement add/remove item when traversal list safely?
Because

Thanks.

 

not that i'm aware of. when you modify the enumeration it gets invalid and i think its a security "feature" to prevent further acess. what you can do is to store the items to remove in a separate collection (list) and after you finished enumeration iterate over this list and remove each element from the original collection. or you use linq to create an entirely new collection after your desire and "overwrite" the initial collection with it.

 

Or use a for loop that goes backwards from the end of the collection to the beginning.

 

Code (csharp):

1. for (int i = collection.Count - 1; i >= 0; i++)
2.     collection.RemoveAt(i);

An enumator simply cannot be used if you modify the collection in any way.

 

i guess you mean i-- .

 

Code (csharp):

1.  
2. list = list.Where(t => t != 2 && t != 4 && t != 6).ToList();
3.