C# Paradigms: Side effects on Lists

Question

I am trying to evolve my understanding of side effects and how they should be controlled and applied.

In the following List of flights, I want to set a property of e

Answer 1

I like using foreach when I'm actually changing something. Something like

foreach (var flight in fResults.Where(f => f.NonStop))
{
  flight.Description = "Fly Direct!";
}

and so does Eric Lippert in his article about why LINQ does not have a ForEach helper method.

But we can go a bit deeper here. I am philosophically opposed to providing such a method, for two reasons.

The first reason is that doing so violates the functional programming principles that all the other sequence operators are based upon. Clearly the sole purpose of a call to this method is to cause side effects.