我不知道你说的合并"是什么意思(数组没有 #merge 方法，只有散列)，但您可以像这样简化代码:

I am not sure what do you mean by "merge" (there is no #merge method on arrays, only on hashes), but you can simplify your code like this:

merged = sources | external_sources

要使其与您的类一起工作，您还需要两个方法:#hash(实例哈希值，用于初步相等性筛选)和 #eql?，用于确认相等:

To make it work with your class, you need two more methods: #hash (instance hash value, used for preliminary equality screening), and #eql?, used to confirm equality:

class Source
  def hash
    url.hash + 1
  end
  # Or delegate it to the url:
  # require 'active_support/core_ext/module/delegation'
  # delegate :hash, to: :url

  def eql? other
    return false if url.nil? || other.url.nil?
    url == other.url
  end
end

#hash 和 #eql? 是每个类都应该具备的基本工具.添加这些之后，#| 和 #& 方法将开始在 Source 实例的数组上运行.

#hash and #eql? are among the basic facilities every class should have. After adding these, #| and #& methods will start to behave on arrays of Source instances.