Swift return type clarification

Question

I see a Swift function written as follows:

func calculation(imageRef: CGImage) -> (red: [UInt], green: [UInt], blue: [UInt]) {

 ...
 ...
}

Answer 1

This called Tuple learn here

it allows to group multiple values under single variable.

Objective c don't support tuple . in objc you have to use dictionary and you have to use key red , green and 'blue with array as value