ruby - 比较不同数组中的多个对象属性

Question

我试图找出一种方法来迭代并从四个不同的来源中删除重复记录。

first_source = [#<Customer:0x007f911e307ad0 @id="123", @name="Whitehall">,#       <Customer:0x007f911e307ad0 @id="124", @name="Whitehall">#<Customer:0x007f911e307ad0 @id="125", @name="Whitehall">]
second_source =  [#<Customer:0x007f911e307ad0 @id="5000", @name="Whitehall">,#<Customer:0x007f911e307ad0 @id="5500", @name="Whitehall">#<Customer:0x007f911e307ad0 @id="123", @name="Whitehall">]
third_source =  [#<Customer:0x007f911e307ad0 @id="800", @name="Whitehall">,#<Customer:0x007f911e307ad0 @id="5000", @name="Whitehall">#<Customer:0x007f911e307ad0 @id="124", @name="Whitehall">]
fourth_source =  [#<Customer:0x007f911e307ad0 @id="4300", @name="Whitehall">,#<Customer:0x007f911e307ad0 @id="800", @name="Whitehall">#<Customer:0x007f911e307ad0 @id="125", @name="Whitehall">]

我试过

customers = []

dup_customers = first_source + second_source + third_source + fourth_source

dup_customers.combination(2).each do |cs1, cs2|
  customers << cs1 unless cs1.id != cs2.id
end

但这确实行不通。

有人可以帮我建议一种方法/策略来遍历这四个集合并找到相等的客户 ID，然后用它做点什么吗？

Answer 1

Array#uniq怎么样？

customers = (first_source + second_source + third_source + fourth_source).uniq

uniq使用Object#eql通过逐元素比较丢弃重复项？，因此要使此方法起作用，您需要实现Customer#eql?.

class Customer
  def eql?(other)
    id == other.id #or however you define equality
  end
end

Answer 2

dup_customers = 
[first_source, second_source, third_source, fourth_source]
.combination(2).flat_map{|s1, s2| s1 & s2}

Answer 3

eql不需要像@pje 那样覆盖。uniq接受一个块（最后一个例子）：

customers = [first_source ,second_source, third_source, fourth_source ].flatten
p customers.uniq{|c| c.id}

Answer 4

您可以使用数组#| （联合运算符）：

customers = first_source | second_source | third_source | fourth_source

它在删除重复项的同时返回两个数组合并的结果：

 ["a", "b", "c" ] | [ "c", "d", "a" ]
 #=> [ "a", "b", "c", "d" ]