OC中有个可变字典和不可变字典。swift中就是let和var来区分可变和不可变的。

新增

var dic = ["name":"000","age":18] as [String : Any]
    dic["title"] = "uuu"
    print(dic)

修改

var dic = ["name":"000","age":18] as [String : Any]
//  dic["title"] = "uuu"
    dic["name"] = "007"
    print(dic)

如果key存在就是修改，不存在就是新增。

删除

var dic = ["name":"000","age":18] as [String : Any]
    dic.removeValue(forKey:"age")
    print(dic)
  字典是通过key来定位值的，key必须是可以’hash 哈希‘  hash就是将字符串变成唯一的'整数'，便于查找，提高字典遍历的速度

遍历

var dic = ["name":"000","age":18,"title":"888"] as [String : Any]
    for e in dic {
        print(e)
        print("\(e.key) \(e.value)")
    }
打印出的结果如下：
(key: "name", value: "000")
name 000
(key: "age", value: 18)
age 18
(key: "title", value: "888")
title 888

//前面的是key，后面的是value,具体的名字可以随便。
    for (key,value) in dic {
        print("\(key) \(value)")
    }

合并

var dic = ["name":"000","age":18,"title":"888"] as [String : Any]
    
    let dic1 = ["name":"da","hegiht":190] as [String : Any]
    
    for e in dic1 {
        dic[e.key] = dic1[e.key]
    }
    //如果key存在会修改，key不存在会新增
    print(dic)

总结

相比OC来说，swift简单一些