一、说明
Swift数组中的类型必须一致，这一点与OC不同
// 数组初始化
var numbers = [0,1,2,3,4,5]
var vowels = ["A","E","I","O","U"]
// 数组的类型： [Int] 或者 Array<Int>
//var numbers: [Int] = [0,1,2,3,4,5]
//var numbers: Array<Int> = [0,1,2,3,4,5]
// 空数组
var emptyArray1:[Int] = []
var emptyArray2:Array<Int> = []
var emptyArray3 = [Int]()
var emptyArray4 = Array<Int>()
// 创建具有默认值的数组(相同元素的数组)
var allZeros = Array<Int>(repeating: 0, count: 5)
//[0,0,0,0,0]
var allZeros2 = [Int](repeating: 0, count: 5)
//[0,0,0,0,0]
二、常用方法
var numbers = [1,2,3,4,5]
var vowels = ["A","E","I","O","U"]
var emptyArray = [Int]()
// 数组长度
vowels.count
// 判空
numbers.isEmpty
emptyArray.isEmpty
// 获取元素
vowels[2]
// 数组越界是一个严重的错误
//vowels[-1]
//vowels[5]
// 获取第一个元素和最后一个元素，返回的是可选型
vowels.first
vowels.last //.first和.last的返回值都为可选型
emptyArray.first
if let firstVowel = vowels.first{
print("The first vowel is " + firstVowel)
}
vowels.first!
vowels[vowels.count-1]
// 获取最小，最大值
numbers.min() //1
vowels.max() //U
// 使用范围
numbers[2..<4] //[3,4]
numbers[2..<numbers.count] //[3,4,5]
// 包含
vowels.contains("A")
vowels.contains("B")
let letter = "A"
if vowels.contains( letter ){
print("(letter) is a vowel")
}
else{
print("(letter) is not a vowel")
}
vowels.index(of: "E") //获取索引，返回值为可选型
if let index = vowels.index(of: "E"){
print("E is a vowel in position (index+1).")
}
else{
print("E is not a vowel.")
}
// 遍历
for index in 0..<numbers.count{
numbers[index]
}
for number in numbers{
print(number)
}
for (index, vowel) in vowels.enumerated(){
//遍历数组索引和元素
print("(index+1): (vowel)")
}
// 比较
var oneToFive = [1,2,3,4,5]
numbers == oneToFive //true
var oneToFive2 = [1,2,4,3,5]
numbers == oneToFive //true
//swift 3.0之前数组是有序的数据集合，swift 3.0后为无序
三、更多操作
var courses = ["A","B","C"]
// 添加元素
courses.append("D") //["A","B","C","D"]
print(courses)
// 数组常量
//使用let定义的数组不可以更改任何内容
courses += ["E"] //+=后面必须和前面的类型一致 //["A","B","C","D","E"]
print(courses)
// 两个数组相加
courses = courses + ["F","G"] //+后面必须是数组
//["A","B","C","D","E","F","G"]
print(courses)
courses.insert("Q", at: 5)
//["A", "B", "C", "D", "E", "Q", "F", "G"]
print(courses)
// 删除元素
courses.removeLast()
//["A", "B", "C", "D", "E", "Q", "F"]
print(courses)
courses.removeFirst()
//["B", "C", "D", "E", "Q", "F"]
print(courses)
courses.remove(at: 4)
//["B", "C", "D", "E", "F"]
//courses.removeAtIndex(10)
print(courses)
//区间删除操作
//courses.removeRange(0..<4)
//courses.removeRange(0..<10)
//print(courses)
//courses.removeAll()
//print(courses)
// 修改元素
courses[0] = "W"
//["W", "C", "D", "E", "F"]
print(courses)
//范围修改
courses[1...3] = ["W","W","W"]
//["W", "W", "W", "W", "F"]
print(courses)
courses[0...3] = ["W"]
//["W", "F"]
print(courses)
