Swift教程之运算符

import Foundation

//4、复合赋值操作符
var a = 1
a += 2

//一元减运算符（一个数值前加了符号-，叫作一元减运算符）
let three = 3
let minusThree = -three //minusThree = -3
let plusThree = -minusThree // plusThree = 3

//一元加运算符（一元加运算符(+)返回的值，不做不论什么变动）
let minusSix = 6
let alsoMinusSix = +minusSix // alsoMinusSix = 6

//6、三元条件运算符
//特别注意：三目运算符里面的(?)前面一定要有至少一个空格
let contentHeight = 40
let rowHeight = contentHeight + (contentHeight > 20 ?

50 : 20) //7、范围运算符 //封闭范围运算符（包含a和b） for index in 1...5 { print("\(index) times 5 is \(index * 5)") } //半封闭的区域运算符（包头不包尾） let names = ["Anna", "Alex", "Brian", "Jack"] let count = names.count for i in 0..<count { print("Person \(i) is called \(names[i])") }