Swift 3.0中文版（1）swift 之旅-Simple V

刚刚接触swift，不怎么喜欢看英文文档，在网上找了半天中文文档一无所获，还是自己简单的翻译一下吧，在这里做个记录，同时也帮助下和我一样不爱看英文的swift小白朋友

Simple Values

使用var和let声明一个常数和变量。常数的值在编译时需分配一个值。可很多地方调用。

var myVariable = 10

myVariable = 20 //此时编译器或自动推断myVariable为整数

let myConstant = 30

如果没有初始值，或初始值没有指定类型，可以通过变量的赋值来指定该类型

let implicitInteger = 70

let implicitDouble = 70.0

let explicitDouble: Double = 70

拼接与转换

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let label = "The width is "

let width = 94

let widthLabel = label + String(width)

输出：

"The width is 94"

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有一种更简单的方法包括在字符串值：写在括号中的值，并写上一个反斜杠（\）在括号。例如:

let apples = 3

let oranges = 5

let appleSummary = "I have \(apples) apples."

let fruitSummary = "I have \(apples + oranges) pieces of fruit."

输出

"I have 8 pieces of fruit."

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let age = 12

let person_age = "我已经 \(age)岁了"

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数组

使用括号（[ ]）创建数组和字典，并通过在括号中的索引或键访问它们的元素。

var shopping = ["catfish","water","tulips"]

shopping[1] = "bottle water" //替换数组中索引为1元素的值

输出

["catfish", "bottle water", "tulips"]

空数组（初始化语法）

let emptyArray = [String]()

or

shopping = []

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字典

var occupations = ["www":"qqqq","eeeee":"www"]

occupations["aaaa"] = "dddd"//向字典中追加数据

输出：

["www": "qqqq", "eeeee": "www", "aaaa": "dddd"]

空字典（初始化语法）

let emptyDictionary = [String: Float]()

or

occupations = [:]

持续更新。。

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