一.数据类型 1.基础类型的封装 Swift provides its own versions of all fundamental C and Objective-C types, including Int for integers, Doubleand Float for floating-point values 2.新类型 Swift introduces advanced types not found in Objective-C, such as tuples. Tuples…

定义有什么,及哪些必须实现. A protocol defines a blueprint of methods, properties, and other requirements that suit a particular task or piece of functionality. Property Requirements The protocol doesn’t specify whether the property should be a stored property or…

结论:扩展无法修改原来的数据结构. Extensions can add new functionality to a type, but they cannot override existing functionality. If you define an extension to add new functionality to an existing type, the new functionality will be available on all existing instan…

原文:Swift语言指南(二)--语言基础之注释和分号 注释 通过注释向自己的代码中注入不可执行的文本,作为你自己的笔记或提示.Swift编译器运行时会忽略注释. Swift的注释与C语言极其相似,单行注释以两个反斜线开头: //这是一行注释 多行注释以/*开始,以*/结束: /* 这也是一条注释, 但跨越多行 */ 与 C 语言的多行注释有所不同的是,Swift 的多行注释可以嵌套在其他多行注释内部.写法是在一个多行注释块内插入另一个多行注释.第二个注释块封闭时,后面仍然接着第一个注释块: /…

Classes, structures, and enumerations can define subscripts, which are shortcuts for accessing the member elements of a collection, list, or sequence. 下标的形式和函数相同,并且set和get合一 subscript(row: Int, column: Int) -> Double 比较: In addition to simple propert…

总结:整个Closure的作用在于简化语言表述形式. 一.闭包的简化 Closure expression syntax has the following general form: { () -> in } reversedNames = names.sorted(by: { (s1: String, s2: String) -> Bool in return s1 > s2 }) Because the sorting closure is passed as an argumen…

一.变量定义 1.常量与变量 Use let to make a constant and var to make a variable. 2.类型与推测 However, you don’t always have to write the type explicitly. Providing a value when you create a constant or variable lets the compiler infer its type. 3.类型转换与字符串 Write the…

1.oc比较: -(BOOL) isKindOfClass: classObj判断是否是这个类或者这个类的子类的实例 -(BOOL) isMemberOfClass: classObj 判断是否是这个类的实例 2.is 类型检查 Use the type check operator (is) to check whether an instance is of a certain subclass type. 3. (as? or as!) 类型转化 Use the conditional f…

1.错误类型与枚举的结合 enum VendingMachineError: Error { case invalidSelection case insufficientFunds(coinsNeeded: Int) case outOfStock } throw VendingMachineError.insufficientFunds(coinsNeeded: 5) 2.异常捕获与栈展开 Error handling in Swift resembles exception handlin…

Swift defines two kinds of initializers for class types to help ensure all stored properties receive an initial value. These are known as designated initializers and convenience initializers. Designated:指定的:特指的 全初始化与部分初始化 Designated Initializers and…