三个存储数据的集合类型：Array，Dictionary，Set

如何在数组中存储有序数据

var names = ["John", "Alice"]

var names = Array<String>()
names.append("John")
names.append("Alice")

var names = String
names.append("John")
names.append("Alice")

如何在字典中存储有序数据

var employee = ["name" : "Taylor", "job": "singer", "location": "USA"]

var employee = String: String
employee["name"] = "Taylor"

var employee3 = Dictionary<String, String>()
employee3["name"] = "Taylor"
查询字典
print(employee3["NAME", default: "nobody"])

如何使用集合快速查询数据

在大量数据时，查找速度比数组快
var people = Set(["Deng xiaoping", "Liu shaoqi", "Mao zedong"])
print(people.contains("Liu shaoqi"))

var people = Set<String>()
people.insert("Deng xiaoping")

如何创建和使用enum

enum Weekday{
case monday
case tuesday
case Wednesday
}

var day = Weekday.monday
day = .tuesday