100 Days of SwiftUI 02

数组按顺序，[red, green, blue]
集合不重复，Set(["red", "green", "blue"])
元组定长度，var name = (first: "Taylor", last: "Swift")
字典有键值，let top3NBAHeights = ["姚明": 2.28]
枚举要分组 enum PostListCategory { case recommend, hot}