class StepCounter { var totalSteps: Int = 0 { willSet(newTotalSteps) { println("About to set totalSteps to (newTotalSteps)") } didSet { if totalSteps > oldValue { println("Added (totalSteps - oldValue) steps") } } } } let stepCounter = StepCounter() stepCounter.totalSteps = 200 // About to set...

//2015.03.06 //赋值运算符 var b = 10 var a = 5 a = b // a 现在等于 10 let (x, y) = (1, 2) // 现在 x 等于 1, y 等于 2

javascript 5 simple types 6 false values number : 0, NaN string : '' boolean : false null undefined

javascript: 1.1.JavaScript:The Good Parts 1.2.Data Structures & Algorithms with JavaScript

1.在可能出现空指针异常的地方,提前加好判断

开启debug,多写try catch,基础很重要