在 Swift 编程语言中，数据结构和类型的合理运用对于高效编程至关重要。接下来，我们将深入探讨数组、集合、字典、区间、元组和可选类型的相关知识。
一、数组（Array）
（一）元素定义
可以通过多种方式定义数组，例如：
var a = [1,2,3]
var b = ["a","b","c"]
var c = [true,false,false]也可以显式指定类型：
var a1:Array<Int> = [1,3,4]
var a2:[Int] = [1,2,3]还可以通过其他方式创建数组，如：
var b1 = Array<Int>()
var b2 = Array<Int>([1,2,3])
var b3 = Array(1...3)
var c1 = Array(repeating: "*", count: 10)（二）元素访问
通过索引访问数组元素：
print(a[0])访问数组的子范围：
print(b[0...2])
print(b[...2])
print(b[1...])（三）数组遍历
以下是几种常见的遍历数组的方式：
for item in b{
print(item,terminator: "-")
}
for(index,value) in b.enumerated(){
print(index,value,terminator: "-")
}
b.forEach{ item in print(item)}（四）元素增删
对数组进行元素的添加和删除操作：
var fruit = ["青苹果","香蕉","芒果"]
fruit.append(b[0])
fruit.append(contentsOf: ["apple","orange"])
fruit += ["西红柿"]
fruit.insert("椰子", at: 1)
fruit.insert(contentsOf: ["a","b"], at: 0)
fruit.removeFirst();
fruit.removeLast();
fruit.remove(at: 0)
fruit.removeSubrange(0...1)（五）数组的变换
对数组进行一些变换操作，例如：
fruit.map{
$0.uppercased()
}（六）数组的方法
数组具有一些实用的方法，如：
print(c1.count) //长度
print(c1.isEmpty) //判空
print(fruit.first?? "") //第一个元素
print(fruit.last?? "") //最后一个元素
print(fruit.randomElement()?? "") //随机访问
num.sort() //排序
//升降
num.sort(by: >)
num.sort(by: <)
fruit.shuffle() //打乱
//反转
var s1 = fruit.reversed();
fruit.reverse()二、集合（Set）
（一）集合定义
var numSet:Set<Int> = [1,2,3]
var numSet2 = Set([1,2,3,4])
var stringSet = Set(["苹果","蓝莓"])（二）集合操作
集合的插入、更新、删除等操作：
var (m,n) = stringSet.insert("香蕉")
stringSet.update(with: "橘子")
stringSet.remove("苹果")
stringSet.removeAll();集合的运算，如并集、差集、交集等：
print(numSet.union(numSet2))
print(numSet.subtracting(numSet2))
print(numSet.intersection(numSet2))
print(numSet.symmetricDifference(numSet2))
print(numSet.isSubset(of: numSet2))
print(numSet.isSuperset(of: numSet2))三、字典（Dictionary）
（一）字典定义
var dict:Dictionary<Int,String> = [:]
var dict2:Dictionary<Int,String> = [1:"apple",2:"orange"]
var dict3 = ["张三":"李四"]（二）字典遍历
通过不同方式遍历字典：
for (key,value) in dict2{
print(key,value)
}
for (key) in dict2.keys{
print(key)
}
for value in dict2.values{
print(value)
}
dict2.forEach{
print($0,$1)
}
dict2.forEach{ (key,value) in
print(key,value)
}四、区间（Range）
区间包括半开区间和闭区间等：
var a = 1...3
var b = "a"..."z"
var c =...100.0
var d = stride(from: 0, to: 10, by: 2)五、元组（Tuple）
元组类似于其他语言中的元组结构：
var p = (1,"张三",10,"age","man")
var p2 = (id:1,name:"张三",age:10,unit:"age",sex:"man")六、可选类型（Optional）
可选类型用于处理可能为空的值：
var i = Int("1")
//Optional=可选类型
print(type(of: i))
//!代表解包 ,如果你确定存在就可以解包
print(i!)
var a:String?="project12"
var b:Optional<Int> = 1
var c:Int? = Optional.some(34)
var d:Int? = Optional.none
print(d == nil)
//a为可选类型，后面会被加？
print(a?.hasPrefix("project"))七、源码
//
// array_study.swift
// StudySwift
//
// Created by YuJun on 2024/7/27.
//
import Foundation
func array_study(){
//元素定义
var a = [1,2,3]
var b = ["a","b","c"]
var c = [true,false,false]
print(a,b,c)
var a1:Array<Int> = [1,3,4]
var a2:[Int] = [1,2,3]
var b1 = Array<Int>()
var b2 = Array<Int>([1,2,3])
var b3 = Array(1...3)
var c1 = Array(repeating: "*", count: 10)
print(a1,a2,b1,b2,b3,c1)
//元素访问
print(a[0])
print(b[0...2])
print(b[...2])
print(b[1...])
//数组的遍历
for item in b{
print(item,terminator: "-")
}
for(index,value) in b.enumerated(){
print(index,value,terminator: "-")
}
b.forEach{ item in print(item)}
//元素增删
var fruit = ["青苹果","香蕉","芒果"]
fruit.append(b[0])
fruit.append(contentsOf: ["apple","orange"])
fruit += ["西红柿"]
fruit.insert("椰子", at: 1)
fruit.insert(contentsOf: ["a","b"], at: 0)
fruit.removeFirst();
fruit.removeLast();
fruit.remove(at: 0)
//删除区间元素
fruit.removeSubrange(0...1)
var num = [1,2,3]
num.insert(contentsOf: 4...6, at: 2)
print(num)
//替换将01替换一下
fruit.replaceSubrange(0...1, with: ["c","d"])
num += (4...7)
print(num)
if(fruit.contains("西红柿")){
print("yes")
}else{
print("no")
}
//这里必须使用$,
var xihongshi = fruit.first(where: {$0=="西红柿"})
var xihongshi2 = fruit.first(where: {n in n=="西红柿"})
var xihongshi3 = fruit.firstIndex(where: {n in n=="西红柿"})
print(xihongshi ?? "")
print(xihongshi2 ?? "")
print(xihongshi3 ?? -1)
print(num.max())
print(num.min())
//数组的变换
fruit.map{
$0.uppercased()
}
print(fruit)
//数组的一些方法
print(c1.count)
print(c1.isEmpty)
print(fruit.first ?? "")
print(fruit.last ?? "")
//输出随机
print(fruit.randomElement() ?? "")
num.sort()
num.sort(by: >)
num.sort(by: <)
//打乱
fruit.shuffle()
//反转
var s1 = fruit.reversed();
fruit.reverse()
let line = "a a a+a"
print(line.split(separator: " "))
print(line.split(whereSeparator: {
c in c == "+" || c == " "
}))
print(fruit.joined(separator: "-"))
}
//Set学习
func set_study(){
//集合Set的定义
var numSet:Set<Int> = [1,2,3]
var numSet2 = Set([1,2,3,4])
var stringSet = Set(["苹果","蓝莓"])
var (m,n) = stringSet.insert("香蕉")
//若存在m=false，不存在m=true并插入
print(m,n)
var (p,q) = numSet.insert(1)
stringSet.update(with: "橘子")//强行插入
stringSet.remove("苹果")
stringSet.removeAll();
//Set的加减交子集合
print(numSet.union(numSet2))//加
print(numSet.subtracting(numSet2))//减
print(numSet.intersection(numSet2))//交
print(numSet.symmetricDifference(numSet2))//差
print(numSet.isSubset(of: numSet2))//子
print(numSet.isSuperset(of: numSet2))//超
print(numSet.randomElement() ?? -1)//超
//其他函数参考数组，遍历也是
}
func dict_study(){
var dict:Dictionary<Int,String> = [:] //空的字典,不写就是数组了
var dict2:Dictionary<Int,String> = [1:"apple",2:"orange"] //空的字典
print(type(of: dict))
print(dict2)
var dict3 = ["张三":"李四"]
print(dict3["张三",default: ""])
for (key,value) in dict2{
print(key,value)
}
for (key) in dict2.keys{
print(key)
}
for value in dict2.values{
print(value)
}
dict2.forEach{
print($0,$1)
}
dict2.forEach{ (key,value) in
print(key,value)
}
print(<#T##items: Any...##Any#>)
//获取随机元素
print(dict2.randomElement())
}
//区间
func range_study(){
var a = 1...3
var b = "a"..."z"
var c = ...100.0
var d = stride(from: 0, to: 10, by: 2)
var e:Range<Int> = 1..<3
var f:ClosedRange<Int> = 1...3
//循环他们只有整数的闭合区间才能便利
for g in a{
print(g)
}
}
//元组 类似于py的元组，实际元组并不存在
func yuan_study(){
var p = (1,"张三",10,"age","man")
var p2 = (id:1,name:"张三",age:10,unit:"age",sex:"man")
print(p.0)
print(p2.name)
}
//可选类型
func emtry_study(){
var i = Int("1")
//Optional=可选类型
print(type(of: i))
//!代表解包 ,如果你确定存在就可以解包
print(i!)
var a:String?="project12"
var b:Optional<Int> = 1
var c:Int? = Optional.some(34)
var d:Int? = Optional.none
print(d == nil)
//a为可选类型，后面会被加？
print(a?.hasPrefix("project"))
}
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