How it works...

A tuple is declared as a comma-separated list of the types it contains, within brackets, for example, (Int, String), as shown in the preceding code. The preceding function, normalisedStarRating, normalizes the rating and creates numberOfStars as the closest number of stars, and ratingString as a display string. These values are then combined into a tuple and returned by placing them, separated by a comma, within brackets as (numberOfStars, ratingString):

let ratingValueAndDisplayString = normalisedStarRating(forRating: 5, ofPossibleTotal: 10) 

Calling our function returns a tuple that we store in a constant called ratingValueAndDisplayString. We can access the tuple's components by accessing the zero-based numbered member of the tuple:

let ratingValue = ratingValueAndDisplayString.0 
print(ratingValue) // 3 - Use to show the right number of stars 

let ratingString = ratingValueAndDisplayString.1 
print(ratingString) // "3 Star Movie" - Use to put in the label 

There is another way to retrieve the values out of a tuple, and it can be achieved as the value is assigned. By specifying a tuple of variable names, each value of the tuple will be assigned to the respective variable name. Consider the following example:

let (nextValue, nextString) = normalisedStarRating(forRating: 8, ofPossibleTotal: 10)
print(nextValue)  // 4
print(nextString) // "4 Star Movie"