Swift 系统学习 08 数组的创建 增删改查

//: Playground - noun: a place where people can playimport UIKit/* * 本节主要内容: * 1.数组的创建和初始化 * 2.数组遍历 * 3.数组元素的增删改查 *//* * value type值类型: 赋值和作为函数参数的时候, 是值的拷贝, 这样的类型称为值类型.  --> Int/String/Character/Bool/Float/Double/Array/Dictionary/Enum/Struct * referce type引用类型: 赋值和作为函数参数的时候, 是地址的赋值和地址的传值, 这样的类型称为引用类型.  --> Class */// 隐式声明数组常量(不可变数组), 并初始化// *****数组中的元素必须相同的类型let arrayOne = [1, 2, 3, 4]// 显示声明let arrayTwo: [Int] = [1, 2, 3, 4]// 显示声明字符串类型的数组let arrayThree: [String] = ["a", "e", "i", "o", "u"]// 四种方式(认识)初始化数组(没有任何元素): 整型类型数组var arrayFour: [Int] = [] //1.推荐var arrayFive = [Int]() //2.推荐var arraySix: Array<Int> = [] //3.var arraySeven = Array<Int>() //4.// 1.是3.的简化形式// 2.是4.的简化形式// 4.Array<Int>结构体的init构造方法// Array是结构体, 提供很多方法(构造数组)var arrayEight = [Int](repeating:3, count: 7)var arrayNine  = Array<Int>(repeating: 10, count: 3)// 数组的遍历for number in arrayNine {    print("Number is \(number)")}// 迭代器循环:下标+元素值for (index, value) in arrayNine.enumerated() {    print("Index is \(index) and value is \(value)")}// 属性arrayNine.startIndexarrayNine.endIndexvar arrayTen = ["hello", "hallo"]arrayFour.min()// 什么时候返回nil: 当数组没有元素的时候arrayNine.max()// 查arrayNine[2]arrayEight[1...3]arrayNine.firstarrayEight.last// 增var oneToFive = [1, 2, 3, 4, 5]oneToFive.append(6)// 数组拼接oneToFive + arrayEightoneToFiveoneToFive += oneToFiveoneToFive// 改oneToFive[0] = 10000oneToFive[1...4] = [20, 30, 40, 50]oneToFive// 删oneToFive.removeFirst()oneToFive.remove(at: 0)var someValue = 10if someValue < 0 {    print("The value is negative!")} else if someValue == 0 {    print("The value is zero!")} else {    print("The value is positive!")}