.shuffle()和.shuffled()是Swift的一部分
原历史问题:
我如何随机或洗牌在Swift数组中的元素?例如,如果我的数组包含52张扑克牌,我想要洗牌数组以洗牌牌组。
.shuffle()和.shuffled()是Swift的一部分
原历史问题:
我如何随机或洗牌在Swift数组中的元素?例如,如果我的数组包含52张扑克牌,我想要洗牌数组以洗牌牌组。
当前回答
这是最简单的方法。导入Gamplaykit到你的VC中,使用下面的代码。在Xcode 8中测试。
import GameplayKit
let array: NSArray = ["Jock", "Ellie", "Sue Ellen", "Bobby", "JR", "Pamela"]
override func viewDidLoad() {
super.viewDidLoad()
print(array.shuffled())
}
如果你想从数组中获得一个打乱的字符串,你可以使用下面的代码..
func suffleString() {
let ShuffleArray = array.shuffled()
suffleString.text = ShuffleArray.first as? String
print(suffleString.text!)
}
其他回答
这个答案详细介绍了如何在Swift 4.2+中使用快速和统一的算法(Fisher-Yates)进行洗牌,以及如何在之前的各种Swift版本中添加相同的功能。每个Swift版本的命名和行为都与该版本的突变和非突变排序方法相匹配。
Swift 4 + 2。
shuffle和shuffle是原生开始Swift 4.2。使用示例:
let x = [1, 2, 3].shuffled()
// x == [2, 3, 1]
let fiveStrings = stride(from: 0, through: 100, by: 5).map(String.init).shuffled()
// fiveStrings == ["20", "45", "70", "30", ...]
var numbers = [1, 2, 3, 4]
numbers.shuffle()
// numbers == [3, 2, 1, 4]
Swift 4.0和4.1
这些扩展将一个shuffle()方法添加到任何可变集合(数组和不安全的可变缓冲区),并将一个shuffled()方法添加到任何序列:
extension MutableCollection {
/// Shuffles the contents of this collection.
mutating func shuffle() {
let c = count
guard c > 1 else { return }
for (firstUnshuffled, unshuffledCount) in zip(indices, stride(from: c, to: 1, by: -1)) {
// Change `Int` in the next line to `IndexDistance` in < Swift 4.1
let d: Int = numericCast(arc4random_uniform(numericCast(unshuffledCount)))
let i = index(firstUnshuffled, offsetBy: d)
swapAt(firstUnshuffled, i)
}
}
}
extension Sequence {
/// Returns an array with the contents of this sequence, shuffled.
func shuffled() -> [Element] {
var result = Array(self)
result.shuffle()
return result
}
}
用法与上述Swift 4.2示例相同。
斯威夫特3
这些扩展将一个shuffle()方法添加到任何可变集合,并将一个shuffled()方法添加到任何序列:
extension MutableCollection where Indices.Iterator.Element == Index {
/// Shuffles the contents of this collection.
mutating func shuffle() {
let c = count
guard c > 1 else { return }
for (firstUnshuffled , unshuffledCount) in zip(indices, stride(from: c, to: 1, by: -1)) {
// Change `Int` in the next line to `IndexDistance` in < Swift 3.2
let d: Int = numericCast(arc4random_uniform(numericCast(unshuffledCount)))
guard d != 0 else { continue }
let i = index(firstUnshuffled, offsetBy: d)
self.swapAt(firstUnshuffled, i)
}
}
}
extension Sequence {
/// Returns an array with the contents of this sequence, shuffled.
func shuffled() -> [Iterator.Element] {
var result = Array(self)
result.shuffle()
return result
}
}
用法与上述Swift 4.2示例相同。
斯威夫特2
(过时的语言:你不能使用Swift 2。x将于2018年7月在iTunes Connect上发布)
extension MutableCollectionType where Index == Int {
/// Shuffle the elements of `self` in-place.
mutating func shuffleInPlace() {
// empty and single-element collections don't shuffle
if count < 2 { return }
for i in startIndex ..< endIndex - 1 {
let j = Int(arc4random_uniform(UInt32(count - i))) + i
guard i != j else { continue }
swap(&self[i], &self[j])
}
}
}
extension CollectionType {
/// Return a copy of `self` with its elements shuffled.
func shuffle() -> [Generator.Element] {
var list = Array(self)
list.shuffleInPlace()
return list
}
}
用法:
[1, 2, 3].shuffle()
// [2, 3, 1]
let fiveStrings = 0.stride(through: 100, by: 5).map(String.init).shuffle()
// ["20", "45", "70", "30", ...]
var numbers = [1, 2, 3, 4]
numbers.shuffleInPlace()
// [3, 2, 1, 4]
斯威夫特1.2
(过时的语言:你不能使用Swift 1。x将于2018年7月在iTunes Connect上发布)
Shuffle是一种可变数组方法
这个扩展将让你洗牌可变数组实例的地方:
extension Array {
mutating func shuffle() {
if count < 2 { return }
for i in 0..<(count - 1) {
let j = Int(arc4random_uniform(UInt32(count - i))) + i
swap(&self[i], &self[j])
}
}
}
var numbers = [1, 2, 3, 4, 5, 6, 7, 8]
numbers.shuffle() // e.g., numbers == [6, 1, 8, 3, 2, 4, 7, 5]
shuffle是一种非突变数组方法
这个扩展可以让你检索一个数组实例的打乱副本:
extension Array {
func shuffled() -> [T] {
if count < 2 { return self }
var list = self
for i in 0..<(list.count - 1) {
let j = Int(arc4random_uniform(UInt32(list.count - i))) + i
swap(&list[i], &list[j])
}
return list
}
}
let numbers = [1, 2, 3, 4, 5, 6, 7, 8]
let mixedup = numbers.shuffled() // e.g., mixedup == [6, 1, 8, 3, 2, 4, 7, 5]
在Swift 4.2中,现在有一个可变shuffle和不可变shuffle的方法。你可以在这里阅读更多关于随机生成和数组的东西。
这是最简单的方法。导入Gamplaykit到你的VC中,使用下面的代码。在Xcode 8中测试。
import GameplayKit
let array: NSArray = ["Jock", "Ellie", "Sue Ellen", "Bobby", "JR", "Pamela"]
override func viewDidLoad() {
super.viewDidLoad()
print(array.shuffled())
}
如果你想从数组中获得一个打乱的字符串,你可以使用下面的代码..
func suffleString() {
let ShuffleArray = array.shuffled()
suffleString.text = ShuffleArray.first as? String
print(suffleString.text!)
}
SWIFT 4
func createShuffledSequenceOfNumbers(max:UInt)->[UInt] {
var array:[UInt]! = []
var myArray:[UInt]! = []
for i in 1...max {
myArray.append(i)
}
for i in 1...max {
array.append(i)
}
var tempArray:[Int]! = []
for index in 0...(myArray.count - 1) {
var isNotFinded:Bool = true
while(isNotFinded){
let randomNumber = arc4random_uniform(UInt32(myArray.count))
let randomIndex = Int(randomNumber)
if(!tempArray.contains(randomIndex)){
tempArray.append(randomIndex)
array[randomIndex] = myArray[index]
isNotFinded = false
}
}
}
return array
}
这里有一些可能更短的内容:
sorted(a) {_, _ in arc4random() % 2 == 0}