在 Swift 中从数组中选择随机数据答案

【问题标题】：Choose random data from an Array in Swift在 Swift 中从数组中选择随机数据
【发布时间】：2017-03-30 04:58:36
【问题描述】：

我想创建一个包含 3 个随机值的新数组，该数组从此列表中提取，用于其他两个视图控制器。不确定如何分配数组以便可以访问这些值。

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
}

}

谢谢

【问题讨论】：

当您说“此列表”时，您所说的列表是什么？您是指您显示的方法中的文本吗？
对不起，我不清楚。我想随机抽出 3 个锻炼。
我添加了一个答案，其中涵盖了我能想到的基本场景 - 希望这会有所帮助。但如果没有，请告诉我:)
你应该使用数组字面量，而不是像那样重复附加值。

标签： arrays swift dictionary random

【解决方案1】：

如果你只是想从allWorkouts 数组中获取一个随机值，那么你可以这样做：

let ndx = Int(arc4random_uniform(UInt32(allWorkouts.count)))
let workout = allWorkouts[ndx]

如果您想随机进行三项锻炼，并且不在乎它们是否独特，那么您可以执行以下操作：

var workouts = [Workout]()
for i in 0 ..< 3 {
    let ndx = Int(arc4random_uniform(UInt32(allWorkouts.count)))
    let workout = allWorkouts[ndx]
    workouts.append(workout)
}

workouts 数组此时将包含三个锻炼。

如果您希望随机项目是唯一的，那么您应该使用 Set 而不是数组，并确保您运行直到获得三个项目，如下所示：

var workouts = Set<Workout>()
while workouts.count < 3 {
    let ndx = Int(arc4random_uniform(UInt32(allWorkouts.count)))
    let workout = allWorkouts[ndx]
    workouts.insert(workout)
}

【讨论】：