Swift单目（一元）运算符被弃用原因和解决

• 大致原因是影响那些把Swift作为第一语言的学习者的学习；Swift的新特性（下面代码对比）完全可以取代这些单目运算符等等
• 弃用原因详情点击这里

for i = 0; i < n; i++ 
{
... 
    
}

for i in 0..<n 
{
... 
    
}

• ++你需要写+=

var x = 1

//Increment
x += 1 //Means x = x + 1 

• 递减--，你需要写-=

var x = 1

//Decrement
x -= 1 //Means x = x - 1

• 对于for循环：

• 增量示例：

• 代替

for var index = 0; index < 3; index ++ {
    print("index is \(index)")
}

• 你可以写：

//Example 1
for index in 0..<3 {
    print("index is \(index)")
}

//Example 2
for index in 0..<someArray.count {
    print("index is \(index)")
}

//Example 3
for index in 0...(someArray.count - 1) {
    print("index is \(index)")
}

• 递减示例：

for var index = 3; index >= 0; --index {
   print(index)
}

• 你可以写：

for index in 3.stride(to: 1, by: -1) {
   print(index)
}
//prints 3, 2

for index in 3.stride(through: 1, by: -1) {
   print(index)
}
//prints 3, 2, 1

for index in (0 ..< 3).reverse() {
   print(index)
}

for index in (0 ... 3).reverse() {
   print(index)
}