A functor is any data type that can be mapped over using
map(), as long it abides by two laws:
map(), the result should be the same as mapping first A then B individually.
Both of those laws sound obvious, but that doesn’t mean they aren’t important. Arrays are functors, sets are functors, optionals are functors, and more.
Available from iOS 8.0 – learn more in my book Pro Swift
Did this solution work for you? Please pass it on!
Other people are reading…
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
Learn Server-Side Swift now!
Take your Swift code to the server and become a full-stack developer with my latest book: Server-Side Swift!