Swift3.0基础语法学习<一>

 //
 //  ViewController.swift
 //  SwiftBasicDemo
 //
 //  Created by 思 彭 on 16/11/15.
 //  Copyright © 2016年 思 彭. All rights reserved.
 //

 import UIKit

 class ViewController: UIViewController {

     override func viewDidLoad() {
         super.viewDidLoad()

         // 1.常量，变量, 类型转换
         let label = "The Width is"
         let width =
         let widthLabel = label + String(width)

         //2.拼接字符串
         let apples =
         let oranges =
         let appleSummany = "I have \(apples) apples"
         let fruitSummany = "I have \(apples + oranges) fruits"

         // 3.数组,字典的使用
         var shoppingList = ["catfish", "water", "tulips", "blue paint"]
         shoppingList[] = "bottle of water"
         var occupations = [
             "Malcolm": "Captain",
             "Kaylee": "Mechanic",
         ]
         // 当没有key，则默认师插入，否则是修改
         occupations["janyne"] = "Public Relations"

         // 4.创建空字典，空数组
         let emptyArray = [String]()
         let emptyDic = [String: Float]()

         // 当类型可以被推断，使用以下方法是错误的
         /*
         let emptyArray1 = []
         let emptyDic1 = [:]
         */

         shoppingList = []
         occupations = [:]

         // 5.if条件判断
         let individualScores = [, ,, , ]
         var teamScore =
         for score in individualScores {
             if score >  {
                 teamScore +=
             }
             else {
                 teamScore +=
             }
         }
         print("teamScore = \(teamScore)")

         // 6.可选类型？
         var optionString: String? = "Hello"
         print(optionString == nil)  // false

         var optionName: String? = "John Appleseed"
         var greeting = "Hello!"
         // 守护
         if let name = optionName {
             greeting = "Hello,\(name)"
         }
         print("greeting = \(greeting)")

         // 7.可选值为nil  ??类似三目 当可选类型不存在为nil，则使用？？后面的默认值
         let nickName: String? = nil
         let fullName: String = "John Appleseed"
         let informalGreeting = "Hi \(nickName ?? fullName)"
         print(informalGreeting)

         // 8.Switch的使用
         let vegetable = "red pepper"
         switch vegetable {
         case "celery":
             print("Add some raisins and make ants on a log.")
         case "cucumber", "watercress":  //多个值
             print("That would make a good tea sandwich.")
         case let x where x.hasSuffix("pepper"): //  条件判断
             print("Is it a spicy \(x)?")
             // 注意：default必须有，否则报错
         default:
             print("Everything tastes good in soup.")
         }

         // 9. 元组的使用  找出最大值
         // 注意： 最后一个，可要可不要，都不会报错
         let interestingNumbers = [
             "Prime" : [, , , , , ],
             "Fibonacci": [, , , , , ],
             "Square": [, , , , ]
         ]
         var largest =
         for (kind, numbers) in interestingNumbers {
             print(kind)
             for number in numbers {
                 if number > largest {
                     largest = number
                 }
             }
         }
         print(largest)

         // 10. while循环   2 可能一次也不执行
         var n =
         while n <  {
             n = n *
         }
         print(n)

         //  repeat while循环   4 注意：至少会执行一次
         var m =
         repeat {
             m = m *
         }while m <
         print(m)

         // 11. ..<的使用  6
         var total =
         for i in ..< {  // 注意不要使用空格，否则报错
             total += i
         }
         print("total = \(total)")

         // 12: 函数和元组
         // 返回值为string
         func greet(person: String, day: String) -> String {

             return "Hello \(person),today = \(day)."
         }
         //函数调用
         let str = greet(person: "SiSi", day: "Tuesday")
         print("str = \(str)")

         // 13. _参数名可以省略
         func greet1 (_ person: String, on day:  String) -> String {

             return "Hello \(person), today is \(day)"
         }
         print(greet1("haha", on: "hahahah"))

         // 14. 元组 －－－ 函数返回多个值
         func calculatevalue(scores: [Int]) -> (min: Int, max: Int, sum: Int) {

             var min = scores[]
             var max = scores[]
             var sum =
             for score in scores {
                 if score > max {
                     max = score
                 }
                 else if score < min {
                     min = score
                 }
                 sum += score
             }
             return (min, max, sum)
         }

         // 函数调用
         let result = calculatevalue(scores: [, , , , ])
         print(result.min)
         print(result.max)
         print(result.)  // 下标调用： 注意： 下标从0开始

         // 15.参数不特定指定数组 每一个值为Int
         func sumOf(numbers: Int...) ->Int {

             var sum =
             for number in numbers {
                 sum += number
             }
             return sum
         }
         print(sumOf(numbers: ,,,))

         // 16.函数的嵌套  15
         func returnFifteen() ->Int {

             var y =
             func add() {
                 y +=
             }
             add()
             return y
         }
         print(returnFifteen())

         // 17. 函数的返回值是一个函数类型  8
         func makeIncrement() -> ((Int) -> Int) {
             func addOne(number: Int) -> Int {
                 return  + number
             }
             return addOne
         }
         var increment = makeIncrement()
         print(increment())

         // 18. 函数的参数是函数类型   true
         func hasAnyMatches(list: [Int], condition: (Int) -> Bool) -> Bool {

             for item in list {
                 if condition(item) {
                     return true
                 }
             }
             return false
         }
         func lessThanTen(number: Int) -> Bool {

             return number <
         }
         var numbers = [, , , ]
         print(hasAnyMatches(list: numbers, condition: lessThanTen))

         // 19. map
         numbers.map({

             (number: Int) -> Int in
             let result =  * number
             return result
             })
         let mappedNumbers = numbers.map { (number) in
               * number
         }
         print(mappedNumbers)
     }
 }

每一条对应每一个语法知识点，注释很详细哟！！！