函数和闭包
使用 func 来声明一个函数
func greet(name: String,day:String) -> String{
return "Hello \(name), today is \(day)."
}
println(greet("Zmsky","HapplyDay”))
使用元祖来返回多个值
func getGasPrices() -> (Double,Double,Double){
return (3.59,3.69,3.79)
}
getGasPrices()
函数的参数数量是可变的,用一个数组来获取它们:
func avgOf(numbers: Int …) -> Int{
var sum = 0
for number in numbers{
sum+=number
}
var avg = sum / numbers.count
return avg
}
函数可以嵌套函数
func returnFifteen() -> Int{
var y = 10
func add(){
y+=5
}
add()
return y;
}
println(returnFifteen())
函数可以作为另外一个函数的返回值
func makeIncrementer() -> (Int -> Int){
func addOne(number: Int) -> Int{
return 1 + number
}
return addOne
}
var increment = makeIncrementer()
println(increment(7))
函数也可以作为当做参数传入另一个函数
func hasAnyMatches(list: [Int], condition : Int -> Bool) -> Bool {
for item in list{
if condition(item){
return true;
}
}
return false;
}
func lessThanTen(number:Int) ->Bool{
return number < 10
}
var numbers = [20,19,7,12]
hasAnyMatches(numbers, lessThanTen)
函数实际上是一种特殊的闭包,可以使用{}赖创建一个匿名闭包。使用in赖分割参数和返回类型。
numbers.map({
(number:Int) -> Int in
let result = 3 * number
return result
})
对象和类
使用class和类名赖创建一个类。类中属性的声明和变量、变量声明一样,唯一的区别就是它们的上下文是类。同样,方法和函数声明也一样。
class Shape{
var numberOfSides = 0
func simpleDescription() -> String{
return "A Shape with \(numberOfSides) sides."
}
}var shape = Shape()
shape.numberOfSides = 100
var shapeDescription = shape.simpleDescription()
println(shapeDescription)
构造函数和继承
class NamedShape{
var numberOfSides : Int = 0
var name: String
init(name:String){
self.name = name; //构造函数
}
//deinit(){
//析构函数
//}
func simpleDescription() -> String{
return "A shape with \(numberOfSides) sides."
}
}class Square:NamedShape{
var sideLength:Double
init(sideLength:Double,name:String){
self.sideLength = sideLength
super.init(name: name)
numberOfSides = 4
}
func area() -> Double{
return sideLength * sideLength
}
override func simpleDescription() -> String {
return "A square with sides of length \(sideLength)."
}
}let test = Square(sideLength: 5.2, name: "my test square")
println(test.area())
println(test.simpleDescription())
属性可以有getter和setter
var perimeter:Double{
get{
return 3.0 * newValue
}
set{
sideLength = newValue / 3.0
}
}