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

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

 ...
 ...
}

The above method returns tuple (A group of different values that you can use in Swift).

You can also return tuple without named parameters:

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

 ...
 ...
}

You can access the return values like this (For un-named tuple parameters):

let returnedTuple = calculation(imagRef)
print(returnedTuple.0) //Red
print(returnedTuple.1) //Green
print(returnedTuple.2) //Blue

or (For named tuple parameters):

let returnedTuple = calculation(imagRef)
print(returnedTuple.red) //Red
print(returnedTuple.green) //Green
print(returnedTuple.blue) //Blue

There is no equivalence of tuple in Objective-C.