Swift 之集合

• 数组
  • 定义
  • 遍历
• 增／删／改
• 合并
• 字典
• 定义
• 遍历
• 增／删／改
• 合并

一 数组

• 定义

//OC中使用 [] 来定义数组, swift 一样,没有 @
        //自动推导结果 [STring] ,表示数组中存放的都是 String
        let arr = ["孙悟空", "唐僧", "猪八戒"]
        print(arr)
        
        // [Int] 表示存放的都是 int
        //Swift中基本数据类型不需要包装
        let arr2 = [1, 2, 3, 4, 5]
        print(arr2)
        
        //CG结构体
        let p = CGPoint(x: 100, y: 200)
        let arr3 = [p]
        print(arr3)
        
        // 混合数组在开发中几乎不用
        //如果数组中类型不一致,会自动推导为 [NSObject]
        // [AnyObject] 为任意类型
        // swift 中的一个类可以没有父类
        let arr4 = ["唐僧", 1, NSValue(cgPoint:p)] as [Any]
        print(arr4)

• 遍历

let arr = ["孙悟空", "唐僧", "猪八戒"]
        //1. 按下标遍历
        print("~~~~~~下标遍历~~~~~~")
        for i in 0..<arr.count {
            print(arr[i])
        }
        
        //2. for in 遍历
        print("~~~~~~for in 遍历~~~~~~")
        for s in arr {
            print(s)
        }
        
        //3. enum block 遍历,同时遍历下标和内容
        print("~~~~~~enum block 遍历~~~~~~")
        for e in arr.enumerated() {
            print(e)
        }
        
        //4. 遍历下标和内容2
        print("~~~~~~enum block 遍历2~~~~~~")
        for (n, s) in arr.enumerated() {
            print("\(n), \(s)")
        }
        
        //5. 反序遍历
        print("~~~~~~反序遍历~~~~~~")
        for c in arr.reversed() {
            print(c)
        }
        
        //6.反序遍历下标和内容
        print("~~~~~~反序遍历下标和内容~~~~~~")
        for (n, s) in arr.enumerated().reversed() {
            print("\(n) \(s)")
        }

• 增删改

//OC 中数组可变 NSMutableArray, 不可变 NSArray, Swift 中可变(var) ,不可变(let)
        var arr = ["孙悟空", "唐僧", "猪八戒"]
        
        // 添加元素
        arr.append("沙僧")
        print(arr)
        
        //修改
        //通过下标,不能越界
        arr[3] = "德华"
        print(arr)
        
        //删除
        arr.remove(at: 2)
        print(arr)
        
        //删除全部,并且保留空间
        arr.removeAll(keepingCapacity:true)
        print("\(arr) , \(arr.capacity)")

• 合并

//数组合并
        var arr1 = ["孙悟空", "唐僧", "猪八戒"] as [Any]
        let arr2 = ["德华", 80] as [Any]
        
        //要合并,类型必须一致
        arr1 += arr2
        print(arr1)

二 字典

• 定义

// 定义
        //OC中用的是 {} , Swift 中用的是 []
        let dict = ["name":"唐僧", "age":90] as [String : Any]
        print(dict)
        
        let arr = [
            ["name":"唐僧", "age":90],
            ["name":"沙僧", "age":9]
        ]
        print(arr)

• 增删改

var dict = ["name":"唐僧", "age":90] as [String : Any]
        //新增, 如果KEY 不存在,就是新增
        dict["title"] = "吃肉"
        print(dict)
        
        //修改 , 通过KEY 取值,修改
        //如果KEY 存在, 就是修改
        dict["name"] = "沙僧"
        print(dict)
        
        // 删除
        dict.removeValue(forKey: "name")
        print(dict)

• 遍历

//遍历
        let dict = ["name":"唐僧", "age":90, "title":"大哥"] as [String : Any]
        for e in dict {
            print(e)
        }
        
        for (n,s) in dict {
            print("\(n) \(s)")
        }

• 合并

//合并
        var dict1 = ["name":"唐僧", "age":90, "title":"大哥"] as [String : Any]
        let dict2 = ["name":"唐僧", "height":90] as [String : Any]
        
        for e in dict2 {
            
            dict1[e.key] = dict2[e.key]
            
        }
        print(dict1)