Ruby on Rails-从哈希数组中按现有键的特定顺序获取值数组

Question

原始数组如下所示：

[{:age=>28, :name=>"John", :id=>1}, {:name=>"David", :age=>20, :id=>2, :sex=>"male"}]

现有密钥的顺序：

[:id, :name, :age] or ['id', 'name', 'age']

结果应为：

[[1, "John", 28], [2, "David", 20]]

谢谢教我

P / s：我正在使用Ruby 1.8.7和Rails 2.3.5

谢谢

Answer 1

这是使用#values_at的好方法：

records = [
  {:age=>28, :name=>"John", :id=>1},
  {:name=>"David", :age=>20, :id=>2, :sex=>"male"}
]

attributes = [:id, :name, :age]

records.collect { |h| h.values_at(*attributes) }
# => [[1, "John", 28], [2, "David", 20]]

Answer 2

映射所有记录，然后按照给定的顺序映射属性，以指定的顺序返回属性的值。

records = [
  {:age=>28, :name=>"John", :id=>1},
  {:name=>"David", :age=>20, :id=>2, :sex=>"male"}
]

attributes = [:id, :name, :age]
records.map do |record|
  attributes.map { |attr| record[attr] }
end