Swift字典

• 字典的定义

//字典的定义
    func demoDict1() -> () {
        //OC使用{}
        //Swift使用[]
        //[key: value] -> [String : NSObject]
        let dict = ["name" : "July", "sex" : "男"]
        print(dict)
        
        //字典数组
        let array: [[String: AnyObject]] = [
            ["name" : "July" as AnyObject, "sex" : "男" as AnyObject],
            ["name" : "june" as AnyObject, "sex" : "女" as AnyObject]
        ]
        print(array)
    }

• 字典的增删改查

//字典的增删改查
    func demoDict2() -> () {
        
        var dict = ["name" : "July", "sex" : "男"]
        
        //增
        dict["tag"] = "coder"
        
        //改 通过 key 取值，key 在字典中必须是唯一的
        //如果 key 存在，就修改
        dict["name"] = "june"
    
        //删 通过 key 来删除
        dict.removeValue(forKey: "sex")
        
        //查 通过 key 来取值
        print(dict["name"] ?? "姓名")
        
        print(dict)
    }

• 字典的遍历

//字典的遍历
    func demoDict3() -> () {
        let dict = ["name" : "July", "sex" : "男"]
        
        //元组(key: String, value: NSObejct)
        for e in dict {
            print("\(e.key) \(e.value)")
        }
        print("------------")
        
        //前面的是key，后边是value，名字可以随意取
        for (key, value) in dict {
            print("\(key) \(value)")
        }
    }

• 字典的合并

//字典的合并
    func demoDict4() -> () {
     
        var dict1 = ["name" : "July", "sex" : "男"]
        var dict2 = ["name" : "june", "sex" : "女", "age" : "20"]
        
        //将dict2合并到dict1
        //dict1 += dict2    //字典不能再像数组一样
        //如果key 存在，会修改
        //如果key 不存在，会新增
        for e in dict2 {
            dict1[e.key] = dict2[e.key]
        }
    }