Question

Can someone explain how the LINQ functions Where(..) and FindAll(..) differ? They both seem to do the same thing…

Answer 1

FindAll() is a function on the List<T> type, it’s not a LINQ extension method like Where. The LINQ extension methods work on any type that implements IEnumerable, whereas FindAll can only be used on List<T> instances (or instances of classes that inherit from it, of course).

Additionally, they differ in actual purpose. Where returns an instance of IEnumerable that is executed on-demand when the object is enumerated. FindAll returns a new List<T> that contains the requested elements. FindAll is more like calling Where(...).ToList() on an instance of IEnumerable.