Question

I need to create a map/array for auto complete from a JSON response and I am looking for the best, most efficient way to do it in Ruby and Rails 3. A portion of the response is below and the working code I have is before it. What is the one line of code I need to create locations for me?

# Need help making this more efficient
response_fields = JSON.parse(response.body)
predictions = response_fields['predictions']
predictions.each do |prediction|
  locations << prediction['description']
end

Sample response from API:

{
   "predictions" : [
     {
       "description" : "Napa, CA, United States",
       "id" : "cf268f9fb9a1b46aed72d59ab85ed40f982763c6",
       "matched_substrings" : [
          {
            "length" : 4,
            "offset" : 0
          }
       ],
     "reference" : "CjQvAAAAqZWNGzqtJf3awNuQNQdnZpl4dBVVXFPrPdz29r1jo1GMWYFuz3KRlK9HgdgszOThEhDeYz_vYgcOPJTaYehF11bUGhR8yH9zqMGV9kenZIo9OTBrSwftgg",
     "terms" : [
        {
           "offset" : 0,
           "value" : "Napa"
        },
        {
           "offset" : 6,
           "value" : "CA"
        },
        {
           "offset" : 10,
           "value" : "United States"
        }
     ],
     "types" : [ "locality", "political", "geocode" ]
  },

Answer 1

You can shorten your code like this:

locations = JSON.parse(response.body)['predictions'].map { |p| p['description'] }