LINQ + Foreach vs Foreach + If

Question

I need to iterate over a List of objects, doing something only for the objects that have a boolean property set to true. I\'m debating between this code

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Answer 1

Most Linq operators such as Where are implemented to support deferred and lazy execution. In your example, the list will be iterated over only once because the enumerator sitting behind the IEnumerable returned by Where will enumerate the list until it finds an item matching the predicate, yields it and will only continue when it is asked for the next element.

From a code perspective, I'd prefer the variant using where, although it could be argued you could declare a local for parameters.Where(p => p.Condition).

Jon Skeet's Edulinq series comes highly recommended, reading some bits of this should help you with your understanding of LINQ operators.