Swift 3.0 For 循环

今天把Swift 项目升级到了 Swift 3.0，好多坑啊，for 循环都抛弃C 语言风格了，让我看看 Swift 3.0 for 循环 的用法吧
被抛弃的C语言风格，如下

for var i = 0;i<4;i++{
}

Swift 3.0 的用法

1. 简单次数循环

 // 利用循环 拼接 字符串
        var ss = ""
        for i in 0...10 {
            ss += "\(i)"
        }
        print("ss: " + ss)

2. 遍历数组

 let array = ["1","2","3","4","5"]
        var ss = ""
        for aa in array {
            ss += aa
        }
        print("ss: " + ss)

3. 得到数组索引

 let array = ["1","2","3","4","5"]
 var sb = ""
        // 如果想知道 索引 怎么办呢
        for bb in array.enumerated() {
            sb += "[\(bb.offset)]\(bb.element)"
            
        }
        print("sb: " + sb)

 // 还可以再改写一下
        var ssb = ""
        for (index, item) in array.enumerated() {
            ssb += "[\(index)]\(item)"
        }
        print("ssb: " + ssb)

4.逆序 遍历

 let array = ["1","2","3","4","5"]
        //        let array33 = [1,2,3,5]
        var sb = ""
        for bb in array.enumerated().reversed() {
            //       \ 后面加 () 小括号里 可以写代码（变量表达式）
            sb += "[\(bb.offset)]\(bb.element)"
            
        }
        print("sb: " + sb)

5.根据条件 取 数组元素

//取出 索引 是2 的倍数的元素
  let array = ["1","2","3","4","5"]
        //        let array33 = [1,2,3,5]
        
        var sb = ""
        
        for bb in array.enumerated().filter({ (index, item)  in index % 2 == 0

        }) {
            
            //       \ 后面加 () 小括号里 可以写代码（变量表达式）
            sb += "[\(bb.offset)]\(bb.element)"
            
        }
        print("sb: " + sb)

6.还有一种

 let array = ["1","2","3","4","5"]
 for i in 0..<array.count{
          print(array[i])
        }