控制流

1

for in 和c用法一致

特殊:

for tickMark in stride(from: 0, to: 12, by: Interval) {

print(tickMark)

}

for tickMark in stride(from: 0, through: 12, by: Interval) {

print(tickMark)

}

2

范围定义

2.1swift中的switch 不用使用break

2.2如果要向下继续执行,可以使用fallthrough 需注意的是 fallthrough 只能向下执行一次case 且不会做条件判断

2.3如果在控制流内使用控制流(嵌套) 可以为控制流添加标签 例如 gameLoop:while

例子: 元组类型

let person = ("Tony",15)

switch person {

case ("Tony",15):

print("我是Tony")

case (_,15):

print("和tony 一般大")

case ("Tony",_):

print("和tony 同名")

default:

print("null")

}

值绑定

let origin = (2,3)

switch origin {

case (let x , 5):

print("x==\(x)")

case (1 , let y):

print("y==\(y)")

case (let x,let y):

print("x==\(x)==\(y)")

}

结合where使用

let yetAnotherPoint = (1, -1)

switch yetAnotherPoint {

case let (x, y) where x == 1:

print("(\(x), \(y)) is on the line x == y")

case let (x, y) where x == -y:

print("(\(x), \(y)) is on the line x == -y")

case let (x, y):

print("(\(x), \(y)) is just some arbitrary point")

}