字典

var dict:Dictionary<String, String> = ["swift":"快速", "java":"爪哇岛"]
var emptyDictionary1:[String:Int] = [:]
var emptyDictionary2:Dictionary<Int,String> = [:]
var emptyDictionary3 = [String:String]()
var emptyDictionary4 = Dictionary<Int,Int>()

print(dict["swift"])
dict["C++"]
if let value = dict["swift"]{
    print("swift 的意思是 － \(value)")
}

dict.count
dict.isEmpty
emptyDictionary1.isEmpty

Array(dict.keys)
Array(dict.values)
for key in dict.keys{
    print("key")
}
for value in dict.values{
    print(value)
}
for (key, value) in dict{
    print("\(key):\(value)")
}
let dict1 = [1:"A",2:"B",3:"C"]
let dict2 = [1:"A",2:"B",3:"C"]
dict1 == dict2

var user = ["name":"bobobo", "password":"123456", "occupation":"programmer"]
user["occuption"] = "freelancer"
user.updateValue("imooc", forKey: "password")

let oldPassword = user.updateValue("imooc", forKey: "password")
if let oldPassword = oldPassword, newPassword = user["password"] where oldPassword == newPassword{
    print("注意：修改后的密码和之前一样，可能导致安全问题")
}

//增
user["email"] = "imooc@imooc.com"
user.updateValue("imooc.com", forKey: "website")
//删
user["website"] = nil
//user.removeValueForKey("email")//或者先进行解包，
if let email = user.removeValueForKey("email"){
    print("电子邮箱\(email)删除成功")
}