Lambda or extension method reference [Answered]

If you have an extension which maps a type A to another type B and you have an enumerable of type A which you want to turn into an enumerable of type B, should you prefer .Select(x => x.ToB()) or .Select(Extensions.ToB)? The first I assume allocates an extra unnecessary lambda which the second doesn't?

I believe there is a very minor performance gain by using the method group over the explicit lambda

however, you shouldn't care about performance until you have a reason to and have identified bottlenecks

I personally think using the method group looks much nicer, so that's what I use when I can

I kind of think the opposite, but good to know

Having to write the name of an extension class feels... weird

i agree - this might be one of the places where i make an exception

it's ultimately up to your preference, in any situation where the performance mattered it would be outshined by using LINQ to begin with

Fair

The first I assume allocates an extra unnecessary lambda which the second doesn't?

No. In fact, up until recently, the first would be more memory-friendly

This is yet another example of trying to optimize based on an implementation detail

In both of these cases, you need an instance of a Func<T1, T2>

One creates a lambda, the other uses a method group. In either case, you need to allocate memory

Fair point

✅ This post has been marked as answered!