如何从该Ruby哈希值中提取值？

Question

I'm using the Foursquare API, and I want to extract the "id" value from this hash

[{"id"=>"4fe89779e4b09fd3748d3c5a", "name"=>"Hitcrowd", "contact"=>{"phone"=>"8662012805", "formattedPhone"=>"(866) 201-2805", "twitter"=>"hitcrowd"}, "location"=>{"address"=>"1275 Glenlivet Drive", "crossStreet"=>"Route 100", "lat"=>40.59089895083072, "lng"=>-75.6291255071468, "postalCode"=>"18106", "city"=>"Allentown", "state"=>"Pa", "country"=>"United States", "cc"=>"US"}, "categories"=>[{"id"=>"4bf58dd8d48988d125941735", "name"=>"Tech Startup", "pluralName"=>"Tech Startups", "shortName"=>"Tech Startup", "icon"=>"https://foursquare.com/img/categories/shops/technology.png", "parents"=>["Professional & Other Places", "Offices"], "primary"=>true}], "verified"=>true, "stats"=>{"checkinsCount"=>86, "usersCount"=>4, "tipCount"=>0}, "url"=>"http://www.hitcrowd.com", "likes"=>{"count"=>0, "groups"=>[]}, "beenHere"=>{"count"=>0}, "storeId"=>""}] 

When I try to extract it by using ['id'] , I get this error can't convert Symbol into Integer . How do I extract the value using ruby? Also, how do I do this for multiple hashes extracting the "id" value each time?

Please pardon my inexperience. Thanks!

Answer 1

It's wrapped in an array, that's what the [ and ] mean on the start and end. But it also looks like this array only one object in it, which is the hash you really want.

So assuming you want the first object in this array:

mydata[0]['id'] # or mydata.first['id'] as Factor Mystic suggests

But usually when an API returns an Array there is a reason (it might return many results instead of just one), and naively plucking the first item from it my not be what you want. So be sure you are getting the kind of data you really expect before hard coding this into your application.

Answer 2

For multiple hashes, if you want to do something with the id (run a procedure of some kind) then

resultsArray.each do |person|
  id = person["id"] #then do something with the id
end

If you want to just get an array containing the ids then

resultsArray.map{|person| person["id"]}  
# ["4fe89779e4b09fd3748d3c5a", "5df890079e4b09fd3748d3c5a"]

To just grab the one item from the array, see Alex Wayne 's answer

Answer 3

To get an array of ids, try: resultsArray.map { |result| result["id"] } resultsArray.map { |result| result["id"] }