LINQ vs regular enumeration

Question

When you have some enumeration methods in some of your types (i.e. a custom collection), is it better to use LINQ syntax or just old school enumeration (for/foreach)?

Using .NET 3.5 is a given.

I am asking this for maximum performance and readability. The application is also designed to be parallel.

Which one would you favor?

Answer 1

Linq queries can be parallelised easily using PLinq (built into .net 4)

I personally find Linq easier to read, but it depends on you as a developer.

foreach (var item in collection)
{
    if (item.Value == SomeOtherValue)
        performSomeProcessing();
}

vs

foreach(var item in collection.Where(a => a.Value == SomeOtherValue))
{
    performSomeProcessing();
}

I think (although i've not personally benchmarked this) that the compiler optimises out the small function calls, so performance should not be noticably different.

Answer 2

If you absolutely must wring every last drop of performance out, then a for/foreach loop is tough to beat for efficiency. However, if you're going for parallelism and readability, the Enumerable<T> extension methods and LINQ win hands down in my book.