ios - #警告: C-style for statement is deprecated and will be removed in a future version of Swift

Question

<分区>

Answer 1

为 init 移除 ；比较;增加 {} 并轻松删除 ++ 和 --。并使用 Swift 漂亮的 for-in 循环

   // WARNING: C-style for statement is deprecated and will be removed in a future version of Swift
   for var i = 1; i <= 10; i += 1 {
      print("I'm number \(i)")
   }

---

swift 2.2:

   // new swift style works well
   for i in 1...10 {
      print("I'm number \(i)")
   }  

---

对于递减索引

  for index in 10.stride(to: 0, by: -1) {
      print(index)
  }

或者你可以像这样使用reverse()

  for index in (0 ..< 10).reverse() { ... }

---

对于float类型(不需要定义任何类型来索引)

 for index in 0.stride(to: 0.6, by: 0.1) {
     print(index)  //0.0 ,0.1, 0.2,0.3,0.4,0.5
 }  

---

swift 3.0:

从 Swift3.0 开始，Strideable 上的 stride(to:by:) 方法已替换为一个自由函数，stride(from :to:by:)

for i in stride(from: 0, to: 10, by: 1){
    print(i)
}

对于 Swift 3.0 中的递减索引，您可以使用 reversed()

for i in (0 ..< 5).reversed() {
    print(i) // 4,3,2,1,0
}

---

除了for each 和stride()，你还可以使用While Loops

var i = 0
while i < 10 {
    i += 1
    print(i)
}

Repeat-While 循环:

var a = 0
repeat {
   a += 1
   print(a)
} while a < 10

查看 The Swift Programming Language Guide 中的控制流