Choose random data from an Array in Swift - arrays

Question

I would like to create a new Array of 3 random values pulled from this list to be used in two other view controllers. Not sure how to assign the Array so those values are accessible.
class WorkoutDataSource {
var allWorkouts:[Workout]
init() {
allWorkouts = []
let bh1 = Workout(title: "Figure 8s - Clockwise", workoutText: "Clockwise around each leg.", color: UIColor.flatNavyBlueColorDark())
allWorkouts.append(bh1)
let bh2 = Workout(title: "Figure 8s - Counter Clockwise", workoutText: "Counter Clockwise around each leg.", color: UIColor.flatNavyBlue())
allWorkouts.append(bh2)
let bh3 = Workout(title: "Dribble Left Handed", workoutText: "Low and Powerfull.", color: UIColor.flatTealColorDark())
allWorkouts.append(bh3)
let bh4 = Workout(title: "Dribble Right Handed", workoutText: "Low and powerfull", color: UIColor.flatTeal())
allWorkouts.append(bh4)
let bh5 = Workout(title: "Around Both Feet", workoutText: "With feet together, circles around ankles-waist-head, work up & down, the full length of body.", color: UIColor.flatSkyBlueColorDark())
allWorkouts.append(bh5)
let bh6 = Workout(title: "Spider Dribble", workoutText: "feet apart, 1 dribble with each hand in front, then 1 dribble with each hand in back. ", color: UIColor.flatSkyBlue())
allWorkouts.append(bh6)
let bh7 = Workout(title: "Helicopter", workoutText: "1 hand in front, 1 hand in back – move your hands from front to back while catching the ball between your legs.", color: UIColor.flatGreenColorDark())
allWorkouts.append(bh7)
let bh8 = Workout(title: "Scissors - Legs Not Moving", workoutText: "One leg forward and one leg back. Dribble between your legs low and fast.", color: UIColor.flatGreen())
allWorkouts.append(bh8)
let bh9 = Workout(title: "Behind the Back", workoutText: ".",color: UIColor.flatGray())
allWorkouts.append(bh9)
let bh10 = Workout(title: "Fingertip Squeeze", workoutText: ".",color: UIColor.flatPink())
allWorkouts.append(bh10)
}
func getWorkOuts() -> [Workout]{
return allWorkouts
}
}
Thank you

Answer 1

If you simply want to get a random value from the allWorkouts array, then you can do something like this:
let ndx = Int(arc4random_uniform(UInt32(allWorkouts.count)))
let workout = allWorkouts[ndx]
If you want to get three workouts at random, and you don't care if they are unique or not, then you can do something like this:
var workouts = [Workout]()
for i in 0 ..< 3 {
let ndx = Int(arc4random_uniform(UInt32(allWorkouts.count)))
let workout = allWorkouts[ndx]
workouts.append(workout)
}
The workouts array will have the three workouts at that point.
If you want the random items to be unique, then you should use a Set instead of an array and ensure that you run till you get three items, like this:
var workouts = Set<Workout>()
while workouts.count < 3 {
let ndx = Int(arc4random_uniform(UInt32(allWorkouts.count)))
let workout = allWorkouts[ndx]
workouts.insert(workout)
}