如何合并两个列表而不使用传统的每个列表

Question

我想合并两个列表。一个是活动记录列表，另一个是简单列表。

每个对象在合并后都会获得权重属性。

我怎么能以更优雅的方式做到这一点。

a_list = [
    {name: "Jack", age: 19},
    {name: "Mark", age: 29},
]

weights = [ 38, 19
]

a_list.join(b_list) = [
    {name: "Jack", age: 19, weight: 38},
    {name: "Mark", age: 29, weight: 19},

]

传统方法

weights.each_with_index do |value, i|
  a_list[i]["weight"] = value
end

Answer 1

做你的传统方法＆＃34;作用：

weights.zip(a_list).zip{|value, h| h["weight"] = value}

要获得上面代码中a_list.join(b_list)所拥有的内容：

weights.zip(a_list).zip{|value, h| h[:weight] = value}

Answer 2

a_list.map.with_index { |x, i| x.merge(weight: weights[i]) }
# => [{:name=>"Jack", :age=>19, :weight=>38}, {:name=>"Mark", :age=>29, :weight=>19}]