Iterate through json response and return one array

Question

Code below returns me all counties as a string, I can see that by using inspect method.

def self.all_counties
    response['ChargeDevice'].each do |charger|
        puts ['ChargeDeviceLocation']['Address']['County'].inspect
    end
end

What would be the right way to store every returned string in one array so I can manipulate it later?

JSON

"ChargeDeviceLocation"   =>   {  
  "Latitude"      =>"51.605591",
  "Longitude"      =>"-0.339510",
  "Address"      =>      { 
     "County"         =>"Greater London",
     "Country"         =>"gb"
  }

Use map instead of each and store the result in a variable. — ndnenkov
– ndnenkov, Commented Oct 3, 2016 at 11:49
You may also find it helpful to use Hash#dig instead of repeated [] calls, to avoid nil errors. — Tom Lord
– Tom Lord, Commented Oct 3, 2016 at 12:01
i.e. charger.dig('ChargeDeviceLocation', 'Address', 'County') — Tom Lord
– Tom Lord, Commented Oct 3, 2016 at 12:02
My guess is that your example raises a TypeError: no implicit conversion of String into Integer exception, because there is no Address index on the ['ChargeDeviceLocation'] array. — spickermann
– spickermann, Commented Oct 3, 2016 at 12:02
Oh, and obviously... returns me all counties as a string -- what string? If an API is returning the data as a string, then you can presumably convert it into array - but I can't tell you how, without knowing what the original string is! — Tom Lord
– Tom Lord, Commented Oct 3, 2016 at 12:05

Kimmo Lehto · Accepted Answer · 2016-10-03 12:30:52Z

2

This works if the response has all the keys for every item:

counties = response['ChargeDevice'].map do |r|
  r.dig('ChargeDeviceLocation', 'Address', 'County')
end

Something like this will give you nils when the tree doesn't have entries for all items:

counties = response['ChargeDevice'].map do |r|
  r.fetch('ChargeDeviceLocation', {}).
    fetch('Address', {}).
    fetch('County', nil)
end

You could also use JSONPath (and ruby JSONPath gem).

require 'jsonpath'
counties = JsonPath.new('$..County').on(response.to_json)

edited Oct 3, 2016 at 12:30

answered Oct 3, 2016 at 12:22

Kimmo Lehto

6,0511 gold badge26 silver badges35 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Iterate through json response and return one array

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related