Welcome to the Lounge

honey the codewitch wrote:

He is putting you on

if (IsRemovable(list[i]))

static void Filter(List<Foo> list)
{
    Queue<Foo> queue = new Queue<Foo>(list);
    list.Clear();
    Foo item = null;
    while (item = queue.Dequeue())
    {
        if (!Remove(item))
            list.Add(item);
    }
}

static void Filter(List<Foo> list) =>
    list.RemoveAll(item => IsRemovable(item)); //I agree with Dave on IsRemovable over Remove.

Jon McKee wrote:

There's no point in involving a Queue in the first place

F-ES Sitecore wrote:

In the original code a List was used to process something that isn't best represented as a List, it was data used as a stack or a queue so using Queue makes that explicit.

F-ES Sitecore wrote:

Also I don't think accessing the last item of a List using an index is very efficient.

Jon McKee wrote:

We don't really know this. All the function represents is a filter operation. The main purpose of the List outside of this function could require random access

Jon McKee wrote:

Numerical indexing is O(1) for array-based List access since underneath everything it's just pointer arithmetic.

static void FilterList(ref List<foo> list)
   {
   list = list.RemoveAll(f => Remove(f)).ToList();
   }

static IEnumerable<Foo> FilterList(List<Foo> list)
   {
   return list.RemoveAll(f => Remove(f));
   }

static void FilterList(List<Foo> list)
   {
   list.RemoveAll(f => Remove(f));
   }

static void FilterList(List<Foo> list)
  => list.RemoveAll(Remove);