Is there any benefit to calling .Any() before .ForEach() when using linq?

Question

I have many methods like the one below:

    void ValidateBuyerRules()
    {
        var nodesWithRules = ActiveNodes.Where(x => x.RuleClass.IsNotNullOrEmpty());

        **if (!nodesWithRules.Any()) return;**

        foreach (var ruleClass in nodesWithRules)
        {
            // Do something here
        }
    }

As you can see, I check if nodesWithRules has any items and exit the method before conducting the foreach statement, but is this unecessary code?

Answer 1

Unless you have some logic after the foreach statement that you want to avoid, that's unnecessary as it will work the same.

When foreach iterates over nodesWithRules detects that there are no items and exit the loop.

Answer 2

If this is linq 2 sql, never do that.

You cause an extra round trip.

Also if you have any other type of IEnumerable, you should avoid that. .net does some tricks for underlying list, but you shouldn't rely on those.