函数和闭包
用函数来定义一个功能
定义一个函数需要在函数名后面用小括号()来添加参数,用->来区分参数类型,名称和返回值的类型
func greet(name:String, day:String) -> String {
return "Hello,\(name),today is \(day)"
}
let greetString = greet(name: "Snow", day: "Monday")
print(greetString)
闭包
let numbers = [1,2,3,4,5,6]
//这个闭包将会轮训数组中的元素,分别给每个元素*3
numbers.map({(number:Int) -> Int in
let result = number * 3
return result
})
//讲数组中的item全部*3
numbers.map({ number in number*3})
对象和类
用class+name 来创建一个类
定义类的一个属性和定义一个常量或者变量一样
用var或者let
class Shape {
var sides = 4
let corners = 4
var name:String
init(name:String) {
self.name = name
}
func simpleDescription() -> String {
return "This \(name) have \(sides) side and have \(corners) corners."
}
}
//在其他类中调用shape类
var shape = Shape(name: "NamedShape")
shape.sides = 8
let descString = shape.simpleDescription()
print(descString)