FirstOrDefault(), SingleOrDefault(), Any(), etc... Which One Is The Fastest?

Question

In regards to the above and/or including other methods, if you are searching for one record, and only one record exists, which one would perform the fastest? For example, I want to make sure that once it finds the value being queried, I'm looking for one that will return it right away without searching through the remaining records.

Answer 1

If you have a think about this you can probably work it out.

FirstOrDefault enumerates the set until it finds a matching item

SingleOrDefault enumerates the entire collection to ensure the item occurs exactly once

This means SingleOrDefault cant be faster than FirstOrDefault. But it does depend a little on the query providers implementation

EDIT:

Any can be implemented even faster. Concider a SQL implementation:

Select Top 1 from myTable //(its not quite this but this implementation but it will be similar)

will execute faster than:

Select Top 1 from myTable where <somecondition>