红宝石镶嵌的优点
Set 的主要优点似乎是保留了独特的元素。但这可以在 Array 中轻松实现，
The main advantage of Set seems to be maintaining unique elements. But that can be easily achieved in Array with,
array = [2,3,4]
array | [2,5,6] # => [2,3,4,5,6]
唯一的独特功能（可能仅适用于少数用例）
The only distinct feature (which could apply to few use-cases) I came across was,
set1 = [1,2,3].to_set
set2 = [2,1,3].to_set
set1 == set2 # => true
[1,2,3] == [2,1,3] # => false
由于 Array 具有各种功能和操作与之相关联，何时以及为什么我应该使用 Set ？
Since Array has various functions and operations associated with it, when and why should I use Set?
有很多链接可以比较 Array 和 Set 但是我还没有遇到 Set 的重要应用。
There are many links that compare Array and Set but I haven't come across significant application of Set.
当然，无论您使用 Set 做什么，都有一种使用 Array 的方法。使用 Set 的优点是，由于它是基于 Hash 实现的，因此对其的大多数操作都是O（ 1）使用 Array 时的复杂度可以为O（n）。
Sure, whatever you can do with Set, there is a way to do it with Array. The advantage of using a Set is that, since it is implemented based on Hash, most operations on it are O(1) complexity, while doing it with Array can be O(n).
示例为：
Set.new([1, 2, 3]).include?(2) # O(1) complexity
[1, 2, 3].include?(2) # O(n) complexity