再探Swift基础

概述基础 tuples // Tuplesvar address = (number: 142, street: "Evergreen Terrace") //起名print(address.number)print(address.street)address.0 = 167print(address.0) //顺序print(address.1)let (house, street 基础
tuples

// Tuplesvar address = (number: 142,street: "Evergreen Terrace") //起名print(address.number)print(address.street)address.0 = 167print(address.0) //顺序print(address.1)let (house,street) = address //赋值print(house)print(street)

strings

// Stringsvar hello = "Hello"hello = hello + " World"print(hello)// String interpolationprint("I live at \(house),\(street)") //替换字符串的内容let str = "I live at \(house + 10),\(street.uppercaseString)";print(str) //一行多句使用分号

numeric

// Numeric types and conversionvar thousands = 1_000 //千元的分隔符（1,000）var radius = 4let pi = 3.14159var area = Double(radius) * Double(radius) * pi  //类型转换问题

for循环

// For loops and rangeslet greeting = "Swift by Tutorials Rocks!"var range = 1...5                           //range是一种类型for i in range {  print("\(i) - \(greeting)")}

while循环

// While loopsvar i = 0while i < 5 {  print("\(i) - \(greeting)")  i++}

if条件

// If statementsfor i in 1...5 {  if i == 5 {    print(greeting.uppercaseString)  } else {    print(greeting)  }}

switch

var direction = "up"switch direction {   //类型问题case "down":  print("Going Down!")case "up":  print("Going Up!")default:  print("Going Nowhere")}var score = 570var prefix: Stringswitch score {case 1..<10:         //类型问题  print("novice")case 10..<100:  print("proficIEnt")case 100..<1000:  print("rock-star")default:  print("awesome")}

optional

var str: String! println(str)if let unwrappedStr = str {   //解包的方式   println("Unwrapped! \(unwrappedStr.uppercaseString)")} else {  println("Was nil")}if str != nil {     //解包前的防御式  str = str.lowercaseString  println(str)}var maybeString: String? = "Hello Swift by Tutorials!"let uppercase = maybeString?.uppercaseString 

array

var array: [Int] = [1,2,3,4,5]println(array[2])array.append(6)array.extend(7...10)println(array)// Challenge solution:array.removeAtIndex(8)array.removeAtIndex(6)array.removeAtIndex(4)array.removeAtIndex(2)array.removeAtIndex(0)println(array)// Challenge solution:  添加任意类型元素的数组var anyArray: [AnyObject] = []anyArray.append(1)anyArray.append("1")println(anyArray)

dictionary

var dictionary: [Int:String] = [1: "Dog",2: "Cat"]println(dictionary[1])dictionary[3] = "Mouse"dictionary[3] = nil   //相当于删除3println(dictionary)// Challenge solution:dictionary.updateValue("Elephant",forKey: 2) //更改println(dictionary)println(dictionary[1])if let value = dictionary[1] {   //从字典取出的为optional类型 拆包  println("Value is \(value)")}

set

var setA: Set = [1,3]setA.insert(1)println(setA)setA.remove(1)println(setA)var setB: Set = [2,6]println(setA.intersect(setB))  //交集// Challenge solution:let divisibleBy3: Set = [3,6,9]let divisibleBy2: Set = [2,8]let union = divisibleBy2.union(divisibleBy3) //并集

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