Swift中级学习 3 字典DIctionary

存储 键-值 数据对的无序数据集

var dict:
[String:String]
=
["1":"ss","2":"dd"]

var dict1:
Dictionary<</span>String,String>
=
["2":"dd","1":"ss"]

print(dict["1"])
//可选性 Optional

dict ==
dict1

dict.count

dict.isEmpty

Array(dict.keys)

Array(dict.values)

//字典遍历

for key in
dict.keys{}

for value in
dict.values{}

for (key,value) in
dict{}

//空字典

var dictt1:
[Int:String] =
[:]

var dictt2:
Dictionary<</span>Int,String>
= [:]

var dictt3 =
[Int:String]()

var dictt4 =
Dictionary<</span>Int,String>()

//改

var user =
["name":"yang","password":"fangfang","sex":"wumen","age":"22"]

user["name"]
= "yangyang"

user.updateValue("yang",
forKey: "name") //返回旧的值

let new
= user.updateValue("yang",
forKey: "name")

//增

user["email"]
= "15711111111@163.com" //不存在的

user.updateValue("15711111111", forKey: "phone")

user

//删

user["phone"]
= nil

user

user.removeValueForKey("email")

user.removeAll()