Can't loop through JSON data because of the error "no implicit conversion of hash into integer"

Question

Hello and good afternoon all!

I am getting an error in my console that states "TypeError: No implicit conversion of hash into integer" and I know that it is referring to my loop in my Ruby class document.

Here is my Ruby file:

require 'HTTParty'
require 'pp'
require 'pry'

=begin
find a way to access the latitude and longitude of the nearest charging station globally
find a way to access the latitude and longitude of the user
create a function that finds the nearest station based on accepting both sets of coordinates and finds the difference
=end

class ChargingStations
    include HTTParty
    attr_accessor :pois
    puts "loading"
    @@latitude = ''

    base_uri 'https://api.openchargemap.io/v2'

    def self.puts_latitude
        puts @@latitude
    end

    def initialize(pois)
        @@pois = pois
        @@latitude = @@pois
        puts @@pois
    end

    def self.put_value
      puts @@latitude
    end

    def self.find_sites
      for i in @@pois do
          puts @@pois[i]
          if @@pois[i]["AddressInfo"]["StateOrProvince"] == "New York"
              puts @@pois[i]
              end
          end
      end

    def self.generate
        response = get('/poi')
        puts "got here"

        if response.success?
            puts "success"
            self.new(response)


        else
            puts "failure"
            raise response.response
        end
    end
end

binding.pry

If you are able to answer the question, please explain why my loop does not work for myself and future developers.

Thank you!

Answer 1

Why don't you give this a try:

class ChargingStations
  include HTTParty

  @@latitude = ''

  base_uri 'https://api.openchargemap.io/v2'

  class << self

    def pois
      @@pois 
    end

    def puts_latitude
      puts @@latitude
    end

    def put_value
      puts @@latitude
    end

    def state_or_provinces
      @state_or_provinces ||= @@pois.map do |poi|
        poi.try(:[],'AddressInfo').try(:[],'StateOrProvince')
      end.uniq
    end

    def find_sites(state_or_province=nil)
      @state_or_province = state_or_province
      @state_or_province ||= 'New York'
      @@pois.select do |poi|
        poi.try(:[],'AddressInfo').try(:[],'StateOrProvince') == @state_or_province
      end
    end

    def generate
      response = get('/poi')
      if response.success?
        @@pois = response.parsed_response
        @@latitude = @@pois
        return true
      else
        puts "failure"
        raise response.response
      end
    end

  end # Class methods

end

Then, in console, I get:

ChargingStations.generate
 => true

ChargingStations.find_sites.count
 => 2

ChargingStations.find_sites.first
 => {"ID"=>112491, "UUID"=>"5EA5B030-AFEF-4CFA-88DF-3A9F6CFFDAB5", "ParentChargePointID"=>nil, "DataProviderID"=>1, "DataProvider"=>{"WebsiteURL"=>"http://openchargemap.org", "Comments"=>nil, "DataProviderStatusType"=>{"IsProviderEnabled"=>true, "ID"=>1, "Title"=>"Manual Data Entry"}, "IsRestrictedEdit"=>false, "IsOpenDataLicensed"=>true, "IsApprovedImport"=>true, "License"=>"Licensed under Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)", "DateLastImported"=>nil, "ID"=>1, "Title"=>"Open Charge Map Contributors"}, "DataProvidersReference"=>nil, "OperatorID"=>5, "OperatorInfo"=>{"WebsiteURL"=>"http://www.chargepoint.net/", "Comments"=>nil, "PhonePrimaryContact"=>"1-888-758-4389", "PhoneSecondaryContact"=>nil, "IsPrivateIndividual"=>false, "AddressInfo"=>nil, "BookingURL"=>nil, "ContactEmail"=>"support@coulombtech.com", "FaultReportEmail"=>"support@coulombtech.com", "IsRestrictedEdit"=>nil, "ID"=>5, "Title"=>"ChargePoint (Coulomb Technologies)"}, "OperatorsReference"=>nil, "UsageTypeID"=>1, "UsageType"=>{"IsPayAtLocation"=>nil, "IsMembershipRequired"=>nil, "IsAccessKeyRequired"=>nil, "ID"=>1, "Title"=>"Public"}, "UsageCost"=>"free", "AddressInfo"=>{"ID"=>112837, "Title"=>"1 Locks Plaza", "AddressLine1"=>"1 Locks Plaza", "AddressLine2"=>nil, "Town"=>"Lockport", "StateOrProvince"=>"New York", "Postcode"=>"14094", "CountryID"=>2, "Country"=>{"ISOCode"=>"US", "ContinentCode"=>"NA", "ID"=>2, "Title"=>"United States"}, "Latitude"=>43.169316400362, "Longitude"=>-78.6954369797903, "ContactTelephone1"=>nil, "ContactTelephone2"=>nil, "ContactEmail"=>nil, "AccessComments"=>"Located at the Lockport Municipal building, \"The Big Bridge\" and the \"Flight of Five\" locks 34 and 35 on the Erie Canal.", "RelatedURL"=>nil, "Distance"=>nil, "DistanceUnit"=>0}, "NumberOfPoints"=>1, "GeneralComments"=>"Located at the \"Big Bridge\" and \"Flight of Five\" locks 34 and 35 and the Lockport Municipal building", "DatePlanned"=>nil, "DateLastConfirmed"=>nil, "StatusTypeID"=>50, "StatusType"=>{"IsOperational"=>true, "IsUserSelectable"=>true, "ID"=>50, "Title"=>"Operational"}, "DateLastStatusUpdate"=>"2018-11-04T12:56:00Z", "DataQualityLevel"=>1, "DateCreated"=>"2018-11-04T05:18:00Z", "SubmissionStatusTypeID"=>200, "SubmissionStatus"=>{"IsLive"=>true, "ID"=>200, "Title"=>"Submission Published"}, "UserComments"=>[{"ID"=>20389, "ChargePointID"=>112491, "CommentTypeID"=>10, "CommentType"=>{"ID"=>10, "Title"=>"General Comment"}, "UserName"=>"Robert Seemueller", "Comment"=>"Located next to the Erie Canal's \"Flight of Five\" locks, downtown shops and restaurants.", "Rating"=>5, "RelatedURL"=>nil, "DateCreated"=>"2018-11-04T05:22:02.4Z", "User"=>{"ID"=>19108, "IdentityProvider"=>nil, "Identifier"=>nil, "CurrentSessionToken"=>nil, "Username"=>"Robert Seemueller", "Profile"=>nil, "Location"=>nil, "WebsiteURL"=>nil, "ReputationPoints"=>289, "Permissions"=>nil, "PermissionsRequested"=>nil, "DateCreated"=>nil, "DateLastLogin"=>nil, "IsProfilePublic"=>nil, "IsEmergencyChargingProvider"=>nil, "IsPublicChargingProvider"=>nil, "Latitude"=>nil, "Longitude"=>nil, "EmailAddress"=>nil, "EmailHash"=>nil, "ProfileImageURL"=>"https://www.gravatar.com/avatar/d8475a6af1852aa7fb2e1263c4ae5fac?s=80&d=mm", "IsCurrentSessionTokenValid"=>nil, "APIKey"=>nil, "SyncedSettings"=>nil}, "CheckinStatusTypeID"=>10, "CheckinStatusType"=>{"IsPositive"=>true, "IsAutomatedCheckin"=>false, "ID"=>10, "Title"=>"Charged Successfully"}}], "PercentageSimilarity"=>nil, "Connections"=>[{"ID"=>158246, "ConnectionTypeID"=>1, "ConnectionType"=>{"FormalName"=>"SAE J1772-2009", "IsDiscontinued"=>nil, "IsObsolete"=>nil, "ID"=>1, "Title"=>"J1772"}, "Reference"=>nil, "StatusTypeID"=>50, "StatusType"=>{"IsOperational"=>true, "IsUserSelectable"=>true, "ID"=>50, "Title"=>"Operational"}, "LevelID"=>2, "Level"=>{"Comments"=>"Over 2 kW, usually non-domestic socket type", "IsFastChargeCapable"=>false, "ID"=>2, "Title"=>"Level 2 : Medium (Over 2kW)"}, "Amps"=>nil, "Voltage"=>nil, "PowerKW"=>nil, "CurrentTypeID"=>nil, "CurrentType"=>nil, "Quantity"=>2, "Comments"=>nil}], "MediaItems"=>[{"ID"=>16951, "ChargePointID"=>112491, "ItemURL"=>"https://s3-ap-southeast-2.amazonaws.com/openchargemap/images/US/OCM112491/OCM-112491.orig.2018110405191125.jpg", "ItemThumbnailURL"=>"https://s3-ap-southeast-2.amazonaws.com/openchargemap/images/US/OCM112491/OCM-112491.thmb.2018110405191125.jpg", "Comment"=>"", "IsEnabled"=>true, "IsVideo"=>false, "IsFeaturedItem"=>false, "IsExternalResource"=>false, "MetadataValue"=>nil, "User"=>{"ID"=>19108, "IdentityProvider"=>nil, "Identifier"=>nil, "CurrentSessionToken"=>nil, "Username"=>"Robert Seemueller", "Profile"=>nil, "Location"=>nil, "WebsiteURL"=>nil, "ReputationPoints"=>289, "Permissions"=>nil, "PermissionsRequested"=>nil, "DateCreated"=>nil, "DateLastLogin"=>nil, "IsProfilePublic"=>nil, "IsEmergencyChargingProvider"=>nil, "IsPublicChargingProvider"=>nil, "Latitude"=>nil, "Longitude"=>nil, "EmailAddress"=>nil, "EmailHash"=>nil, "ProfileImageURL"=>"https://www.gravatar.com/avatar/d8475a6af1852aa7fb2e1263c4ae5fac?s=80&d=mm", "IsCurrentSessionTokenValid"=>nil, "APIKey"=>nil, "SyncedSettings"=>nil}, "DateCreated"=>"2018-11-04T05:19:00Z"}, {"ID"=>16952, "ChargePointID"=>112491, "ItemURL"=>"https://s3-ap-southeast-2.amazonaws.com/openchargemap/images/US/OCM112491/OCM-112491.orig.2018110405224211.jpg", "ItemThumbnailURL"=>"https://s3-ap-southeast-2.amazonaws.com/openchargemap/images/US/OCM112491/OCM-112491.thmb.2018110405224211.jpg", "Comment"=>"", "IsEnabled"=>true, "IsVideo"=>false, "IsFeaturedItem"=>false, "IsExternalResource"=>false, "MetadataValue"=>nil, "User"=>{"ID"=>19108, "IdentityProvider"=>nil, "Identifier"=>nil, "CurrentSessionToken"=>nil, "Username"=>"Robert Seemueller", "Profile"=>nil, "Location"=>nil, "WebsiteURL"=>nil, "ReputationPoints"=>289, "Permissions"=>nil, "PermissionsRequested"=>nil, "DateCreated"=>nil, "DateLastLogin"=>nil, "IsProfilePublic"=>nil, "IsEmergencyChargingProvider"=>nil, "IsPublicChargingProvider"=>nil, "Latitude"=>nil, "Longitude"=>nil, "EmailAddress"=>nil, "EmailHash"=>nil, "ProfileImageURL"=>"https://www.gravatar.com/avatar/d8475a6af1852aa7fb2e1263c4ae5fac?s=80&d=mm", "IsCurrentSessionTokenValid"=>nil, "APIKey"=>nil, "SyncedSettings"=>nil}, "DateCreated"=>"2018-11-04T05:23:00Z"}, {"ID"=>16953, "ChargePointID"=>112491, "ItemURL"=>"https://s3-ap-southeast-2.amazonaws.com/openchargemap/images/US/OCM112491/OCM-112491.orig.2018110405240797.jpg", "ItemThumbnailURL"=>"https://s3-ap-southeast-2.amazonaws.com/openchargemap/images/US/OCM112491/OCM-112491.thmb.2018110405240797.jpg", "Comment"=>"", "IsEnabled"=>true, "IsVideo"=>false, "IsFeaturedItem"=>false, "IsExternalResource"=>false, "MetadataValue"=>nil, "User"=>{"ID"=>19108, "IdentityProvider"=>nil, "Identifier"=>nil, "CurrentSessionToken"=>nil, "Username"=>"Robert Seemueller", "Profile"=>nil, "Location"=>nil, "WebsiteURL"=>nil, "ReputationPoints"=>289, "Permissions"=>nil, "PermissionsRequested"=>nil, "DateCreated"=>nil, "DateLastLogin"=>nil, "IsProfilePublic"=>nil, "IsEmergencyChargingProvider"=>nil, "IsPublicChargingProvider"=>nil, "Latitude"=>nil, "Longitude"=>nil, "EmailAddress"=>nil, "EmailHash"=>nil, "ProfileImageURL"=>"https://www.gravatar.com/avatar/d8475a6af1852aa7fb2e1263c4ae5fac?s=80&d=mm", "IsCurrentSessionTokenValid"=>nil, "APIKey"=>nil, "SyncedSettings"=>nil}, "DateCreated"=>"2018-11-04T05:24:00Z"}], "MetadataValues"=>nil, "IsRecentlyVerified"=>true, "DateLastVerified"=>"2018-11-04T05:22:02.4Z"}

ChargingStations.find_sites('WA').count
 => 1

Answer 2

In general, when you use the construct for foo in fooArray to iterate over a Array, the foo is not the index but the actual item located in that position. So if you wanted your algorithm to work with minimal modifications, the "right" way would look like:

@@pois.each_index do |i|
  puts @@pois[i]
  // rest of the algorithm ommited
end

In your case, assuming that the structure of your JSON data is something like [{lat: 10, lng: 10},{lat:5, lng:8}, {lat: 9, lng: -3], you are basically trying to do @@pois[{lat: 10, lng: 5}]], which will give you the exact "no implicit conversion" error that you're getting. You could just use i directly like puts i or i["AddressInfo"]["StateOrProvince"] and get the right answer.

However, as it has been mentioned in the comments, a more idiomatic approach would be @@pois.each do |poi|. And an even more idiomatic approach would be to rename that ugly-looking "pois" everywhere and make it

@@positions.each do |position|
  puts position
  if position["AddressInfo"]["StateOrProvince"] == "New York"
    puts position
  end
end

Explicit variable names is the Ruby thing to do :)

And assuming the first puts is just a general test to see it's working and you actually want to only print the ones that are in New York...

@@positions.each do |position|
  puts position if position["AddressInfo"]["StateOrProvince"] == "New York"
end

And if you want to make that a one liner:

@@positions.each { |pos| puts pos if pos["AddressInfo"]["StateOrProvince"] == "New York" }

(yeah, I know I just talked about explicit variable names but there is no need to be too rigid about it)