Swift学习笔记 -- 简单值

//打印会自动换行

print("Hello, Swift!")

//声明常量

let no1Int = 70;

let no1Double = 10.0;

//若初始化时未提供足够信息（没有初始值），可以在变量后面指定类型，用冒号隔开。

let no1Float: Float =1314.521

print(no1Float,no1Int,no1Double)

let label =
"我就问你 Kevin
帅吗？"

let answer = "帅得飞起"

let score = 100

//值在转化为另一种类型时从不具有隐含性。如果需要转化值到另一种类型，请明确性地为值进行格式转换。

let answerLabel =
label + answer +
String(score)

print(answerLabel)

//声明变量

var no1Variable =
250

print(no1Variable)

no1Variable = 213

print(no1Variable)

//更简单的方法将值转换为String：将值写在括号中，并在括号前添加一个反斜杠。例：

let apples = 3

let oranges = 5

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

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

print(appleSummary)

print(fruitSummary)

//通过 []创建一个数组和字典，通过 index和 key
获取对应的值

var shoppingList = ["apple","6plus","ipad","iwatch"]

shoppingList[1] ="iphone 6s"

var occupations = ["Beijing":"Captain","Tokyo":"Hot"]

occupations["Kevin"] ="GaoFuShuai"

//为了防止类型信息被更改，空数组列用[]，空字典用[:]进行初始化
- 例如，为变量赋新值和给函数传递参数的时候。

var fruitArray = []

var fruitDictionary = [:]