Written by Paul Hudson @twostraws
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.
Get the ultimate experience
The Swift Power Pack includes my first six books for one low price, helping you jumpstart a new career in iOS development – check it out!