创建随机数量的类实例-Swift

Question

I'm trying to generate a random 'workout' with a random number of exercises.

Each exercise needs to have a name (from an array) and a number of reps (a random number which will eventually have 'upper and lower' bounds depending on what type of exercise it is (eg up to 10 for push ups, but only 1 for '500m row'. But that can come later! For now, I'm trying to work out how to generate a random number of class instances (I'll then pass these via a segue and put in a tableView, assuming that's possible)

Here's my code, which is just in a playground for now :

import UIKit

let exerciseArray = ["squats", "pushups", "lunges", "jumping jacks"]

class exerciseInWorkout {

    var exerciseName : String
    var exerciseReps : Int

    init(name: String, reps: Int) {
        exerciseName = name
        exerciseReps = reps
    }

}

let randomkey = Int(arc4random_uniform(4))
let numberOfExercisesInWorkout = Int(arc4random_uniform(10))

// Manually creating a new object of exerciseInWorkout with a random exercise and a random number of reps

let exerciseOne = exerciseInWorkout(name:exerciseArray[randomkey],     reps:Int(arc4random_uniform((30))))

//print result to make sure it works

print(exerciseOne.exerciseName, exerciseOne.exerciseReps)

//Have some function here which creates a number of class instances based on the "numberOfExercisesInWorkout" constant

If I'm completely on the wrong track here feel free to tell me but I think I'm not far off (hopefully...)

Answer 1

There are probably a lot of different (valid) approaches to this. One of which could be something like this:

let exerciseArray = ["squats", "pushups", "lunges", "jumping jacks"]

struct Exercise {
    let name: String
    let reps: Int
}

func randomInt(upperBound: UInt32) -> Int {
    return Int(arc4random_uniform(upperBound))
}

let numberOfExercisesInWorkout = randomInt(upperBound: 10)

let exercises: [Exercise] = (1...numberOfExercisesInWorkout).map { _ in
    let randomKey = randomInt(upperBound: UInt32(exerciseArray.count))
    return Exercise(name: exerciseArray[randomKey], reps: randomInt(upperBound: 10))
}

print(exercises)

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Which ouputs something like this:

[Exercise(name: "lunges", reps: 8), Exercise(name: "jumping jacks", reps: 6), Exercise(name: "lunges", reps: 4), Exercise(name: "squats", reps: 9), Exercise(name: "jumping jacks", reps: 5), Exercise(name: "squats", reps: 9)]

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Note : You could also modify the ( randomInt ) helper function to take into account a lowerBound I guess