ForEach -- where are you?

Question

Possible Duplicate:
Why is there not a ForEach extension method on the IEnumerable interface?

I love the .ForEach method on List<T> in C#. How is this not one of the suite of Extension Methods on IEnumerable<T>?

Why do I have to call .ToList() my collection in order to call an action on each element? Please tell me why? Thank you.

List<T>.ForEach(Action<T> action);

See this link for a pretty definitive explanation: http://blogs.msdn.com/b/ericlippert/archive/2009/05/18/foreach-vs-foreach.aspx — dlev, Jul 13 '11 at 02:38
There are no elements available to loop over with foreach until you actually execute the query by using ToList() — JK., Jul 13 '11 at 02:39
@JK - If I can 'Count()' and get 'First()' why cant I act on each element? — Glenn Ferrie, Jul 13 '11 at 02:41
@Glenn It's not my answer, it's someone else's. I try to just post links as comments unless they're directly to documentation. — dlev, Jul 13 '11 at 02:45
Because Count and First are for querying, whereas ForEach is for acting. Eric Lippert has the exact reasoning here: http://blogs.msdn.com/b/ericlippert/archive/2009/05/18/foreach-vs-foreach.aspx — Michael Stum, Jul 13 '11 at 02:51

score 3 · Answer 1 · answered Jul 13 '11 at 02:36

Language INtegrated Query (LINQ). Not Language Integrated Extensions (LIEs).

You are particularly speaking of LINQ-to-objects. The other LINQs (to-SQL, to-XML), etc. would have more trouble implementing arbitrary logic.

Nothing stops you from implementing it yourself, though.

public static class Extensions
{
   public static void ForEach<T> (this IEnumerable<T> items, Action<T> action)
   {
      foreach (T item in items)
      {
         action (item);
      }
   }
}

ok, so why not an extension method with all of the others on IEnumerable-T?? — Glenn Ferrie, Jul 13 '11 at 02:37

score 1 · Accepted Answer · edited May 23 '17 at 12:05

1

There's been much discussion over this topic:

See:

edited May 23 '17 at 12:05

Community

1
1

answered Jul 13 '11 at 02:47

Justin Shield

2,360
14
12

ForEach -- where are you?

2 Answers2