Intelligent way of removing items from a List while enumerating in C#

Question

I have the classic case of trying to remove an item from a collection while enumerating it in a loop:

List myIntCollection = new List()         


        

Answer 1

If you're interested in high performance, you can use two lists. The following minimises garbage collection, maximises memory locality and never actually removes an item from a list, which is very inefficient if it's not the last item.

private void RemoveItems()
{
    _newList.Clear();

    foreach (var item in _list)
    {
        item.Process();
        if (!item.NeedsRemoving())
            _newList.Add(item);
    }

    var swap = _list;
    _list = _newList;
    _newList = swap;
}