ruby : How to sort an array of hash in a given order of a particular key

Question

我有一个散列数组，id 是散列中的键之一。我想根据 ID 值的给定顺序对数组元素进行排序。

假设我的数组(size=5)是:

[{"id"=>1. ...}, {"id"=>4. ...}, {"id"=>9. ...}, {"id"=>2. ...}, {"id"=>7. ...}]

我想对数组元素进行排序，使其 id 的顺序如下:

[1,3,5,7,9,2,4,6,8,10]

所以预期的结果是:

[{'id' => 1},{'id' => 7},{'id' => 9},{'id' => 2},{'id' => 4}]

Answer 1

这里是任何自定义索引的解决方案:

def my_index x 
  # Custom code can be added here to handle items not in the index.
  # Currently an error will be raised if item is not part of the index.
  [1,3,5,7,9,2,4,6,8,10].index(x) 
end

my_collection = [{"id"=>1}, {"id"=>4}, {"id"=>9}, {"id"=>2}, {"id"=>7}]
p my_collection.sort_by{|x| my_index x['id'] } #=> [{"id"=>1}, {"id"=>7}, {"id"=>9}, {"id"=>2}, {"id"=>4}]

然后你可以按照你想要的任何方式格式化它，也许这样更漂亮:

my_index = [1,3,5,7,9,2,4,6,8,10]
my_collection.sort_by{|x| my_index.index x['id'] }