From 0ef193aaecd6c8972c474abe9f84d4100764088e Mon Sep 17 00:00:00 2001 From: cdpath Date: Sat, 26 Dec 2015 14:43:33 +0800 Subject: [PATCH 1/3] Translated an-absolute-beginners-guide-to-swift.md --- TODO/an-absolute-beginners-guide-to-swift.md | 213 ++++++++++--------- 1 file changed, 108 insertions(+), 105 deletions(-) diff --git a/TODO/an-absolute-beginners-guide-to-swift.md b/TODO/an-absolute-beginners-guide-to-swift.md index e1a5bc4d602..b0805a74cc3 100644 --- a/TODO/an-absolute-beginners-guide-to-swift.md +++ b/TODO/an-absolute-beginners-guide-to-swift.md @@ -1,70 +1,71 @@ > * 原文链接: [Absolute Beginner's Guide to Swift](http://blog.teamtreehouse.com/an-absolute-beginners-guide-to-swift) * 原文作者 : [Amit Bijlani](http://blog.teamtreehouse.com/author/amitbijlani) * 译文出自 : [掘金翻译计划](https://github.com/xitu/gold-miner) -* 译者 : +* 译者 : [cdpath](https://github.com/cdpath) * 校对者 : -* 状态 : 待定 +* 状态 : 翻译完成 +* 说明 : 注释皆为译者注 -**Update:** We're excited to announce that Treehouse has launched its [Learn Swift](http://teamtreehouse.com/learn-swift "Learn Swift on Treehouse") courses as of today! Learn Swift basics, Swift functions, and build two real apps with Swift. [Learn more about our Swift courses](http://teamtreehouse.com/learn-swift "Learn Swift on Treehouse"). +**更新:** 我们高兴地宣布 Treehouse 已经发布了[学习 Swift 教程](http://teamtreehouse.com/learn-swift "Learn Swift on Treehouse")！快来学习 Swift 基础知识， Swift 函数并用 Swift 构建两个真正的 App吧。 [了解详情](http://teamtreehouse.com/learn-swift "Learn Swift on Treehouse")。 -## Why Swift? +## 为什么选择 Swift？ -In case you haven't heard, Apple just introduced a new language for iOS and OSX developers called Swift. It has come to light that Swift was in the works since 2010, which is 2 years after the first SDK was released. Apple saw the limitations of Objective-C which is almost 30 years old and decided it was time for a change. However, in true Apple fashion, they did not want to release a half-baked language. They realized that no matter the drawbacks of Objective-C, they could still push the envelope with it, and so they did. +如果你没听过 Swift，这里简单介绍一下。Apple 刚刚为 iOS 和 OSX 开发者带来了全新的 Swift 语言。我们知道 Apple 自 2010 年开始开发 Swift ，距第一个 SDK [^1: iPhone OS 1.x: SDK]发布已有两年。Apple 认识到了 Objective-C 的局限性，毕竟它已有 30 年的历史，是时候作出改变了。但是以 Apple 的风格，发布一个半成品语言不可想象的。Apple 认为尽管 Objective-C 有不少缺点，依然可以将其利用到极致，Apple 做到了。 -It's been six years since the release of the first SDK and 1.2 million apps have been submitted to the App Store. Millions of developers have suffered through learning the arcane syntax and limitations of Objective-C. Recently, a vocal few decided to [speak](http://ashfurrow.com/blog/we-need-to-replace-objective-c) [up](http://informalprotocol.com/2014/02/replacing-cocoa/) expressing their woes about the outdated language. +在第一个 SDK 发布后的六年里，有 120 万个 App 发布到了 App Store。数百万的程序员领略了 Objective-C 语法的晦涩难懂并认识到了其局限性。最近有几个直言不讳的家伙决定站出来[大胆](http://ashfurrow.com/blog/we-need-to-replace-objective-c)[表达](http://informalprotocol.com/2014/02/replacing-cocoa/)他们对这一过时语言的困扰。 -Swift probably took a little over four years to create and is the result of the work of many smart individuals who love crafting a new language. They looked all around for inspiration and not only created a new language but tools to along with it that would make it easy to learn. +Swift 是众多热爱打磨新语言的聪明人历时四年多的杰作。他们到处寻求灵感，不仅仅发明了这门新语言还创造了相关工具让其易于学习。 -When talking about Swift, Apple refers to three key considerations: Safe, Modern and Powerful. It lives up to all those three things. Outlined below are some of the very basics you need to get up and running with Swift. If you already know a programming language, then you will see a lot of similarities with other modern languages. You might even wonder why they had to invent a whole new language, but that is discussion for another blog post. +谈到 Swift 之时，Apple 提到了三点重要考量：安全，现代，强大。Swift 名符其实。只要了解下文概括的基础知识之后就可以上手 Swift。如果已了解一门编程语言，你会在 Swift 上看到许多其他现代编程语言的影子。你或许会问为什么一定要重新发明一门语言，这已经超出本文的范畴，我们会在其他博文中讨论。 -## Using Swift +## 用 Swift -Firstly, you will have to download and install [Xcode 6](https://developer.apple.com/devcenter/ios/index.action). Once you have installed it, open it up and select File from the menu -> New -> Select Source on the left under either iOS or OSX -> Playground. Give your playground a name and you are ready to get started. +首先，下载并安装 [Xcode](https://developer.apple.com/devcenter/ios/index.action)。搞定之后，打开 Xcode，在菜单栏依次点击：File -> New -> 在左侧选择来源（iOS 或 OSX 都可以） -> Playground。给 Playground 起个名字就可以开始啦。 -Alternatively, you could use the REPL (Read Evaluate Print Loop) from the terminal. +要不然就打开终端使用 REPL（读取﹣求值﹣输出循环）。 -**Instructions to run from the terminal:** +**使用终端指导** -1\. Open up terminal +1\. 打开终端 -2\. If you have two or more versions of Xcode installed then you will need to select Xcode 6 as your default version. If you are only running Xcode 6 then skip ahead to step 3\. If you are only running Xcode 6 then skip ahead to step 3, otherwise go ahead and run the following line: +2\. 如果装有多个版本的 Xcode，请将 Xcode 6[^2: 最新版为 Xcode 7] 设置为默认版本。如果只有 Xcode 6 直接跳到第三步，不然就输入下面这行： `sudo xcode-select -s /Applications/Xcode6-Beta.app/Contents/Developer/` -At the time of writing this post beta version of Xcode 6 was named “Xcode6-Beta”. Please check your app name in the “Applications” folder to write out the appropriate path when using `xcode-select`. +在撰写本文时 Xcode 6 的 beta 版叫做“Xcode6-Beta”。在用 `xcode-select` 的时候务必去“应用程序”文件夹下检查一下 Xcode 的名字。 -3\. To start the REPL type: +3\. 要开启 REPL，输入： `xcrun swift` -## Fundamentals +## 基础 -### Variables +### 变量 -As with every programming language you have variables which allow you to store data. To declare a variable you have to use the keyword `var`. +和其他编程语言一样，Swift 使用变量存储数据。要声明一个变量，必须显式使用 `var` 关键字。 var greeting: String = "Hello World" -The above code instructs the system that you want to create a variable named `greeting` which is of type `String` and it will contain the text, “Hello World”. +上述代码告诉系统你想要创建一个名为 `greeting` 的变量，`String` 类型，内容是 “Hello World” 文本。 -Swift is smart enough to infer that if you are assigning a string to a variable and in fact that variable will be of type string. So you need not explicitly specify the type as in the above example. A better and common way of writing the above example would be: +如果将字符串赋值给变量，Swift 会聪明地推断出变量应该是字符串类型的。所以上例不用显式地指定变量类型。所以上例最好写成： - var greeting = "Hello World" // Inferred type String + var greeting = "Hello World" // 推断为字符串类型 -Variables can be modified once created so we could add another line and change our `greeting` to something else. - - var greeting = "Hello World" // Inferred type String +变量一经创建就可以修改，所以可以给 `greeting` 变量再加上一行，做出修改： + var greeting = "Hello World" // 推断为字符串类型 + greeting = "Hello Swift" -While writing an application there are many instances where you don't want to change a variable once it has been initialized. Apple has always had two variants of types mutable and immutable. Mutable meaning the variable can be modified and immutable that it cannot be modified. They prefer immutability by default which means that the values aren't going to change and it makes your app faster and safer in a multi-threaded environment. To create an immutable variable you need to use the keyword `let`. +写应用程序时经常会遇到一旦将变量初始化就不再修改它的场景。Apple 设计了两种类型：可变的和不可变的。「可变」意味着变量可被修改，「不可变」则不可修改。默认情况下都是「不可变」的，这意味着值不会改变，由此 App 可以在多线程环境下更快更安全地运行。要创建不可变的常量请使用关键字 `let`。 -If we change our greeting example to use `let` instead of `var` then the second line will give us a compiler error because we cannot modify `greeting`. +如果将上面 greeting 例子中的 `var` 修改为 `let`，第二行会报编译器错误，因为不能修改 `greeting`。 let greeting = "Hello World" - greeting = "Hello Swift" //Compiler error + greeting = "Hello Swift" //编辑器错误 -Lets take another example so you understand why and when to use `let`. +再举一个例子说明为什么使用以及何时应该使用 `let`。 let languageName: String = "Swift" @@ -74,28 +75,28 @@ Lets take another example so you understand why and when to use `let`. let isAwesome: Bool = true -The above example not only shows us the various types that are available in Swift but it also shows us that the reason to use `let`. Aside from the version number of the Swift language everything else remains constants. You might argue that `isAwesome` is debatable but I'll let you reach that conclusion once you reach the end of this post. +上述代码不仅展示了 Swift 支持的多种类型，还道出了使用 `let` 的原因。除了 Swift 的版本号[^3: 即 `version` 变量]，其他都是常量。你或许会争辩说 `isAwesome` 是否是常数存在争议，但是读完本文你就会同意我的结论。 -Since the type is inferred we should simply write: +因为类型可以推断出来，可以简写如下： - let languageName = "Swift" // inferred as String + let languageName = "Swift" // 推断为字符串类型 - var version = 1.0 // inferred as Double + var version = 1.0 // 推断为 Double 型 - let introduced = 2014 // inferred as Int + let introduced = 2014 // 推断为 Int 型 - let isAwesome = true // inferred as Bool + let isAwesome = true // 推断为 Bool 型 -### Strings +### 字符串 -In our above example we have been writing the String type. Lets see how we can concatenate two strings by using the `+` operator. +上面的例子用到了字符串类型。接下来我们看看如何用 `+` 操作符来拼接两个字符串。 let title = "An Absolute Beginners Guide to Swift" let review = "Is Awesome!" let description = title + " - " + review // description = "An Absolute Beginners Guide to Swift - Is Awesome!" -Strings have a powerful string interpolation feature where it's easy to use variables to create a strings. +字符串具有强大的字符串插值特性，可以用变量来创建字符串。 let datePublished = "June 9th, 2014" @@ -103,108 +104,108 @@ Strings have a powerful string interpolation feature where it's easy to use vari // postMeta = "Blog Post published on: June 9th, 2014" -In all the above examples, I have been using the keyword `let` which means you cannot modify the string once it has been created. However, if you do need to modify the string then simply use the keyword `var`. +上述所有例子使用的都是 `let`，也就是说这些字符串创建之后不可修改。当然如果需要修改字符串，那么用 `var` 关键字就好了。 -### Other Types +### 其他类型 -Besides strings you have `Int` for whole numbers. `Double` and `Float` for floating-point numbers and `Bool` for boolean values such as: true of false. These types are inferred just as a string so you need not explicitly specify them when creating a variable. +除字符串类型以外，还有 `Int` 表示整数，`Double` 和 `Flout` 表示浮点数以及`Bool` 表示布尔值（比如真或假）。这些类型都可以跟字符串类型一样通过类型推导自动得到，所以创建变量时没有必要显式写出类型。 -A `Float` and `Double` vary in precision and how large of a number you can store. +`Float` 和 `Double` 的区别在于精度不同，能存储的最大数字也不同。 -* Float: represents a 32-bit floating-point number and the precision of Float can be as little as 6 decimal digits. -* Double: represents a 64-bit floating point number and has a precision of at least 15 decimal digits. +* Float：代表 32位 浮点型数字，精度只有 6 位十进制数字。 +* Double：代表 64位 浮点型数字，精度可达 15 位十进制数字。 -By default when you write a floating-point number it is inferred as a Double. +默认情况下浮点数会被推断为 `Double` 类型。 - var version = 1.0 // inferred as Double + var version = 1.0 // 推断为 Double 型 -You can explicitly specify a `Float`. +当然也可以显式声明为 `Float` 型。 var version: Float = 1.0 -## Collection Types +## 集合类型 -### Array +### 数组 -Collections come in two varieties. Firstly, an array which is a collection of data items which can be accessed via an index beginning with 0. +集合类型有两种。第一种是数组类型，也就是可以通过从 0 开始的索引访问的数据元素的集合。 var cardNames: [String] = ["Jack", "Queen", "King"] - // Swift can infer [String] so we can also write it as: + // Swift 可以推断出 cardNames 是 [String] 类型，所以可以写成： var cardNames = ["Jack", "Queen", "King"] // inferred as [String] -You can create two types of arrays: an array of a single type or an array with multiple types. Swift is keen on being safe so it prefers the former but can accommodate the later with generic types. The example above is an array of strings which means that it is a single type array. +数组有两种：包含单一数据类型的数组和包含多种数据类型的数组。Swift 追求安全性，所以更偏好前者，但是也可以用通用类型类来兼容后者。上面例子是字符串数组，也就是单一数据类型的数组。 -To access an item from the array you need to use the subscript: +要访问数组中的元素需要使用下标： println(cardNames[0]) -Note: we used a function above called `println` which will print the value “Jack” to the console and then add a new line. +注意：我们使用 `println` 函数[^4: Swift 2 中请使用 `print`]将 “Jack” 这个值打印到控制台，后面还加上了换行。 -### Modifying an Array +### 修改数组 -Lets create a new array that contains a todo list. +新建一个数组来存储代办事项列表吧： var todo = ["Write Blog","Return Call"] -Make sure that you use the keyword `var` so that we can modify our array. +要确保使用了 `var` 关键字，这样才可以修改数组。 -To add another item to our `todo` array we use the ‘+=' operator: +要在 `todo` 数组中加入新元素要用到 `+=` 操作符： todo += "Get Grocery" -To add multiple items to our `todo` array we simply append an array: +要在 `todo` 数组中加入多个元素很简单，追加到数组上就好： todo += ["Send email", "Pickup Laundry"] -To replace an existing item in the array simply subscript that item and provide a new value: +要替换数组中已有的元素，下标索引出要修改的元素再赋一个新值就好了： todo[0] = "Proofread Blog Post" -To replace an entire range of items: +要替换数组的一定范围内的元素的话就要提供该范围内的元素的新值： todo[2..<5] =="" ["pickup="" laundry","get="" grocery",="" "cook="" dinner"]="" <="" code=""> -### Dictionary +### 字典 -The other collection type is a `Dictionary` which is similar to a Hash Table in other programming languages. A dictionary allows you to store key-value pairs and access the value by providing the key. +第二种集合类型是 `字典`，类似于其他编程语言中的哈希表。字典可以存储_键值对_，可以根据键访问对应的值。 -For example, we can specify our cards by providing their keys and subsequent values. +比如，可以通过指定键和对应的值来指定一组扑克牌： var cards = ["Jack" : 11, "Queen" : 12, "King" : 13] -Above we have specified the card names as the keys and their corresponding numerical value. Keys are not restricted to the `String` type, they can be of any type and so can the values. +上面代码中的扑克牌名是键，对应数字是值。键不一定非得是 `字符串` 类型，完全可以是任意类型，值也是如此。 -### Modifying a Dictionary +### 修改字典 -What if we wanted to add an “ace” to our `cards` dictionary? All we have to do is use the key as a subscript and assign it a value. Note: `cards` is defined as a `var` which means it can be modified. +如果要给 `cards` 字典添加一张 “A” 要怎么办呢？其实只要把键当作下标，赋给它一个新值就好了。注意：`cards` 被声明为 `var` 变量，也就是说值可以改变。 cards["ace"] = 15 -We made a mistake and want to change the value of “ace”. Once again just use the key as the subscript and assign it a new value. +上面这行我们搞错了 “A” 对应的数字，需要将其改正。只要再将键作为下标，给它一个新值就好了。 cards["ace"] = 1 -To retrieve a value from the dictionary +检索字典中的值： println(cards["ace"]) -## Control Flow +## 控制流 -### Looping +### 循环 -What it good is a collection if you cannot loop over it? Swift provides `while`, `do-while`,`for` and `for-in` loops. Lets take a look at each one of them. +如果都不能用来循环，那么集合类型还有什么好处呢？Swift 提供了 `while`，`do-while`，`for` 以及 `for-in` 循环。我们来依次看一看。 -The easiest one of them is the `while` loop which states while something is `true` execute a block of code. It stops execution when that condition turns to `false`. +所有循环中 `while` 是最简单的，其表示只要条件为 `真` 就不断执行代码段。当条件变为 `假` 时，停止执行。 while !complete { println("Downloading...") } -Note: the exclamation mark before the variable `complete` denotes not and is read as “not complete”. +注意：`complete` 变量前面的感叹号表示「非」，读作「不满足」。 -Likewise, you have the `do-while` loop which ensures that your block of code is executed at least once. +同样地，使用 `do-while` 循环可以保证代码块至少执行一次。 var message = "Starting to download" do { @@ -212,42 +213,42 @@ Likewise, you have the `do-while` loop which ensures that your block of code is message = "Downloading.." } while !complete -Subsequent calls to the `println` statement will print “Downloading..” +上面代码中稍后调用的 `println` 表达式会打印「下载中......」。[^5: 第一次调用的 `pringln` 会打印「开始下载」] -You have the regular for loop where you can specify a number and increment that number to a certain value: +使用一般形式的 for 循环可以指定一个数字然后不断增加那个数字，直到一个特定的值。 for var i = 1; i < cardNames.count; ++i { println(cardNames[i]) } -Or you can simply use the `for-in` variant where it creates a temporary variable and assigns it a value while iterating over the array. +还可以使用简单的 `for-in` 形式，它会创建一个临时变量，在遍历数组时对其赋值。 for cardName in cardNames { println(cardName) } -The above code will print out all the card names in the array. We can also use a range. A range of values is denoted by two dots or three dots. +上述代码会打印数组中的全部扑克牌名。还可以使用「区间」来实现。值的「区间」用两个或三个点表示。 -For example: +比如： -* 1…10 – is a range of numbers from 1 to 10\. The three dots are known as a closed range because the upper limit is inclusive. -* 1..<10 1="" –="" is="" a="" range="" of="" numbers="" from="" to="" 9.="" the="" two="" dots="" with="" lesser-than="" sign="" known="" as="" half-closed="" because="" upper="" limit="" non-inclusive.<="" li=""> +* 1...10 表示 1 到 10 的数字「区间」。这三个点表示闭区间，因为包括最大值。 +* 1..<10 表示 1 到 9 的数字「区间」。两个点和小于号表示半开半闭区间，因为不包括最大值。 -Lets print out the 2 times table using `for-in` with a range: +比如用 `for-in` 结合区间来打印 2 的乘法表： for number in 1...10 { println("\(number) times 2 is \(number*2)") } -We can also iterate over the `cards` dictionary to print out both the key and the value: +还可以遍历 `cards` 字典同时打印键和值： for (cardName, cardValue) in cards { println("\(cardName) = \(cardValue)") } -### If Statements +### If 表达式 -To control the flow of our code we of course have an `if` statement. +要控制代码流程当然要用 `if` 表达式。 if cardValue == 11 { println("Jack") @@ -257,15 +258,16 @@ To control the flow of our code we of course have an `if` statement. println("Not found") } -Note: The `if` syntax can have parenthesis but they are optional. However, the braces {} are mandatory unlike other languages. +注意：`if` 的语法允许有括号，不强制要求。但是大括号 `{}` 必须有，这点和其他编程语言不同。 + +### Switch 表达式 -### Switch Statement +Swift 中的 `switch` 表达式功能丰富特性众多。下面是 `swift` 表达式的一些基本规则： -The `switch` statement in Swift is very versatile and has a lot of features. Some basic rules about the switch statement: -* It doesn't require a break statement after each case statement -* The `switch` is not limited to integer values. You can match against any values such as: `String`, `Int`, `Double` or any object for that matter. -* The switch statement must match against every value possible if not you must have a `default` case which makes your code safer. If you don't provide a `case` for every value or a `default` then you will get a compiler error saying: “switch must be exhaustive”. +* 每个 `case` 表达式后面不要求有 `break` 表达式。 +* `switch` 没有被限制为整数类型，其可以用来匹配多种类型的值：`String`，`Int` 或者 `Double`，而且还可以使用任何对象。 +* `switch` 表达式必须对应每一个可能值，否则得使用 `default case` 让代码更安全。如果没有为每一个可能值都提供 `case` 也没有使用 `default` 那么会报编译错误：“switch 必须是完备的”。 switch cardValue { case 11: @@ -276,7 +278,7 @@ The `switch` statement in Swift is very versatile and has a lot of features. Som println("Not found") } -Lets say you have a distance variable and you are trying to print a message based on distance. You can use multiple values for each case statement: +假如有一个距离变量，需要根据距离值打印消息。可以利用多个 `case` 表达式来使用多个值。 switch distance { case 0: @@ -289,7 +291,7 @@ Lets say you have a distance variable and you are trying to print a message base println("too far") } -There are times when even multiple values are limiting. For those instances you can use ranges. What if any distance greater than 10 and less than 100 was considered far? +还有时候使用多个值还是有局限性。这时就要使用区间了。想一想，如果要把距离大于 10 且小于 100 定义为「远」，应该如何表达呢？ switch distance { case 0: @@ -306,42 +308,43 @@ There are times when even multiple values are limiting. For those instances you } -Can you guess what the above code will print? +猜猜上述代码会打印什么出来？ -## Functions +## 函数 -Finally, we have been using `println` in a lot of our examples which is an example of how to use a function. But how can you create your own function? +最后要提的是函数，我们之前在很多例子中使用过的 `println` 就是函数。要如何自己定义一个函数呢？ -It is simple, you have to use the keyword `func` and provide it with with a name. +要定义一个函数非常简单，使用 `func` 关键字再起个函数名就好了。 func printCard() { println("Queen") } -What good is a function if it always going to just print “Queen” as the card name. What if we want to pass it a parameter so it can print any card name? +如果一个函数只能打印扑克牌名（比如 “Queen”）似乎没什么用处。如果能够给它传入一个参数然后打印任意的扑克牌名呢？[^6: 也没什么用......] func printCard(cardName: String) { println(cardName) } -Of course, we are not restricted to just one parameter. We can pass in multiple parameters: +当然，并没有限制说只能使用一个参数。传入多个参数是可以的。 func printCard(cardName: String, cardValue: Int) { println("\(cardName) = \(cardValue)") } -What if we simply wanted our function to build a string and return the value instead of printing it? Then we can specify a return it which is specified at the end of the function declaration followed by an array `->`. +如果只想让函数构建一个字符串并返回字符串的值而不是打印出来要怎么做呢？只要在函数声明的结尾（`->` 之后）指定返回值（类型）就好了。 func buildCard(cardName: String, cardValue: Int) -> String { return "\(cardName) = \(cardValue)" } -Above we are saying that we are creating a function named `buildCard` which takes in two parameters and returns a String. +上述代码的意思是创建名为 `buildCard` 的函数，接受两个参数，返回一个字符串。 + +## 总结 -## Conclusion +如果能坚持读到这里，恭喜你已经掌握了 Swift 基础！虽然这些还只是 Swift 的皮毛，你或许需要花一些时间吸收这些知识。需要学习的东西还有很多，在 Treehouse 我们致力于向你提供学习 Swift 所需的全部知识。 -If you have made it this far, then congratulations! You are now well-versed in the basics of Swift. That is a lot to take in, but it is only scratching the surface and what Swift is capable of. There is so much more to learn, and here at Treehouse we are working on courses to provide you with all the Swift learning that you need. Stay tuned for more! +如果想要学习 Swift 基础，在 Treehouse 报名参加 Amit 的[学习 Swift](http://teamtreehouse.com/learn-swift "Learn Swift on Treehouse") 课程吧。 -If you want to learn the basics of Swift, take Amit's [Learn Swift](http://teamtreehouse.com/learn-swift "Learn Swift on Treehouse") courses on Treehouse. From 3893036879d51abcbe5aafcee491f57fb9c339c5 Mon Sep 17 00:00:00 2001 From: cdpath Date: Wed, 30 Dec 2015 13:09:18 +0800 Subject: [PATCH 2/3] Fixed typo --- TODO/an-absolute-beginners-guide-to-swift.md | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/TODO/an-absolute-beginners-guide-to-swift.md b/TODO/an-absolute-beginners-guide-to-swift.md index b0805a74cc3..7d544d953dd 100644 --- a/TODO/an-absolute-beginners-guide-to-swift.md +++ b/TODO/an-absolute-beginners-guide-to-swift.md @@ -12,7 +12,7 @@ 如果你没听过 Swift，这里简单介绍一下。Apple 刚刚为 iOS 和 OSX 开发者带来了全新的 Swift 语言。我们知道 Apple 自 2010 年开始开发 Swift ，距第一个 SDK [^1: iPhone OS 1.x: SDK]发布已有两年。Apple 认识到了 Objective-C 的局限性，毕竟它已有 30 年的历史，是时候作出改变了。但是以 Apple 的风格，发布一个半成品语言不可想象的。Apple 认为尽管 Objective-C 有不少缺点，依然可以将其利用到极致，Apple 做到了。 -在第一个 SDK 发布后的六年里，有 120 万个 App 发布到了 App Store。数百万的程序员领略了 Objective-C 语法的晦涩难懂并认识到了其局限性。最近有几个直言不讳的家伙决定站出来[大胆](http://ashfurrow.com/blog/we-need-to-replace-objective-c)[表达](http://informalprotocol.com/2014/02/replacing-cocoa/)他们对这一过时语言的困扰。 +在第一个 SDK 发布后的六年里，有 120 万个 App 提交到了 App Store。数百万的程序员领略了 Objective-C 语法的晦涩难懂并认识到了其局限性。最近有几个直言不讳的家伙决定站出来[大胆](http://ashfurrow.com/blog/we-need-to-replace-objective-c)[表达](http://informalprotocol.com/2014/02/replacing-cocoa/)他们对这一过时语言的困扰。 Swift 是众多热爱打磨新语言的聪明人历时四年多的杰作。他们到处寻求灵感，不仅仅发明了这门新语言还创造了相关工具让其易于学习。 @@ -108,7 +108,7 @@ Swift 是众多热爱打磨新语言的聪明人历时四年多的杰作。他 ### 其他类型 -除字符串类型以外，还有 `Int` 表示整数，`Double` 和 `Flout` 表示浮点数以及`Bool` 表示布尔值（比如真或假）。这些类型都可以跟字符串类型一样通过类型推导自动得到，所以创建变量时没有必要显式写出类型。 +除字符串类型以外，还有 `Int` 表示整数，`Double` 和 `Float` 表示浮点数以及`Bool` 表示布尔值（比如真或假）。这些类型都可以跟字符串类型一样通过类型推导自动得到，所以创建变量时没有必要显式写出类型。 `Float` 和 `Double` 的区别在于精度不同，能存储的最大数字也不同。 @@ -262,7 +262,7 @@ Swift 是众多热爱打磨新语言的聪明人历时四年多的杰作。他 ### Switch 表达式 -Swift 中的 `switch` 表达式功能丰富特性众多。下面是 `swift` 表达式的一些基本规则： +Swift 中的 `switch` 表达式功能丰富特性众多。下面是 `switch` 表达式的一些基本规则： * 每个 `case` 表达式后面不要求有 `break` 表达式。 From 3d39666d3d72a4f724fa26edce61cf8272744d08 Mon Sep 17 00:00:00 2001 From: cdpath Date: Mon, 4 Jan 2016 23:32:46 +0800 Subject: [PATCH 3/3] improve the translation --- TODO/an-absolute-beginners-guide-to-swift.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/TODO/an-absolute-beginners-guide-to-swift.md b/TODO/an-absolute-beginners-guide-to-swift.md index 7d544d953dd..fc31d606505 100644 --- a/TODO/an-absolute-beginners-guide-to-swift.md +++ b/TODO/an-absolute-beginners-guide-to-swift.md @@ -16,7 +16,7 @@ Swift 是众多热爱打磨新语言的聪明人历时四年多的杰作。他们到处寻求灵感，不仅仅发明了这门新语言还创造了相关工具让其易于学习。 -谈到 Swift 之时，Apple 提到了三点重要考量：安全，现代，强大。Swift 名符其实。只要了解下文概括的基础知识之后就可以上手 Swift。如果已了解一门编程语言，你会在 Swift 上看到许多其他现代编程语言的影子。你或许会问为什么一定要重新发明一门语言，这已经超出本文的范畴，我们会在其他博文中讨论。 +谈到 Swift 之时，Apple 提到了三点重要考量：安全，现代，强大。Swift 名符其实。下文概括了一些上手 Swift 所必备的基础知识。如果已了解一门编程语言，你会在 Swift 上看到许多其他现代编程语言的影子。你或许会问为什么一定要重新发明一门语言，这已经超出本文的范畴，我们会在其他博文中讨论。 ## 用 Swift