Question

I have List<T> data and Predicate<T> condition.

What way should I use to clear data depending on condition result?

• Option 1:

  var del = data.Where(i => condition);
  data.RemoveAll(i => del.Contains(i));
  

• Option 2:

  var del = data.Where(i => condition);
  for (int i = 0; i < del.Count; i++)
      data.Remove(del[i]);
  

• Option 3:

  var del = data.Where(i => condition);
  foreach (var i in del)
     data.Remove(i);
  

• Option 4:

  data = data.Where(i => !condition);
  

• Any other?

Answer 1

How about:

data.RemoveAll(condition);

Note that your fourth option won’t work without a call to ToList().