哈希数组放入Rails的下拉列表中

Question

In Rails, I have an array of hashes (@things) that looks something like this:

[
{"id"=>1, "name"=>"firstThing"}, 
{"id"=>2, "name"=>"secondThing"}, 
{"id"=>3, "name"=>"thirdThing"}
]

I also have an object with a thingId with a value of 2 (@otherThing.thingId = 2). I would like to turn the array into a dropdown with an empty option and with the secondThing option selected (because it has id = 2).

I successfully built this with some if, else and using that to output some <option value... code, then realized that's probably not the Railsy way to do it. Not sure exactly how to railsify this the best way. I have reviewed the documentation at http://api.rubyonrails.org/classes/ActionView/Helpers/FormOptionsHelper.html , but I'm not sure how my array of hashes fits in with all of that.

Answer 1

The options_for_select helper can take an array like this:

[
  ["firstThing", "1"],
  ["secondThing", "2"],
  ["thirdThing", "3"]
]

(The select helper uses options_for_select internally, so, depending on your use case, it makes this even simplier) So all you need is to convert your array of hashes into the above form. For example like this:

arrayForOptions = arrayOfHashes.collect { |item|
  [item['name'], item['id']]
}