Ruby: Extract from deeply nested JSON structure based on multiple criteria

Question

I want to select any marketId of marketName == 'Moneyline' but only those with countryCode == 'US' || 'GB' OR eventName.include?(' @ '). (space before and after the @). I tried different combos of map and select but some nodes don't have countryCode which complicates things for me. This is the source, but a sample of what it might look like:

{"currencyCode"=>"GBP",
"eventTypes"=>[
    {"eventTypeId"=>7522,
    "eventNodes"=>[
        {"eventId"=>28024331,
        "event"=>
            {"eventName"=>"EWE Baskets Oldenburg v PAOK Thessaloniki BC"
            },
            "marketNodes"=>[
                {"marketId"=>"1.128376755",
                "description"=>
                    {"marketName"=>"Moneyline"}
                },
                {"marketId"=>"1.128377853",
                "description"=>
                    {"marketName"=>"Start Lublin +7.5"}
                }}}]},
        {"eventId"=>28023434,
        "event"=>
            {"eventName"=>"Asseco Gdynia v Start Lublin",
            "countryCode"=>"PL",
            },
            "marketNodes"=>
                [{"marketId"=>"1.128377853", ETC...

When you give an example please do the following. 1. Make it a valid Ruby object (no "ETC...") so readers can run their code against your example. 2. Show the desired return value. 3. Simplify the example by stripping out extraneous elements. Since it's obvious that hash = JSON.parse(File.read('data.json')), here you may want to just present the hash rather than the JSON string and make no reference to JSON. 4. Assign a variable to each input object (e.g, h = {currency...}). This allows readers to refer to those variables in answers and comments without having to define them. — Cary Swoveland
– Cary Swoveland, Commented Nov 20, 2016 at 21:55

Community · Accepted Answer · 2017-05-23 10:32:49Z

2

Based on this previous answer, you just need to add a select on eventNodes :

require 'json'

json = File.read('data.json')
hash = JSON.parse(json)

moneyline_market_ids = hash["eventTypes"].map{|type|
  type["eventNodes"].select{|event_node|
    ['US', 'GB'].include?(event_node["event"]["countryCode"]) || event_node["event"]["eventName"].include?(' @ ')
  }.map{|event|
    event["marketNodes"].select{|market|
      market["description"]["marketName"] == 'Moneyline'
    }.map{|market|
      market["marketId"]
    }
  }
}.flatten

puts moneyline_market_ids.join(', ')
#=> 1.128255531, 1.128272164, 1.128255516, 1.128272159, 1.128278718, 1.128272176, 1.128272174, 1.128272169, 1.128272148, 1.128272146, 1.128255464, 1.128255448, 1.128272157, 1.128272155, 1.128255499, 1.128272153, 1.128255484, 1.128272150, 1.128255748, 1.128272185, 1.128278720, 1.128272183, 1.128272178, 1.128255729, 1.128360712, 1.128255371, 1.128255433, 1.128255418, 1.128255403, 1.128255387

If you want to keep the country code and name information with the id:

moneyline_market_ids = hash["eventTypes"].map{|type|
  type["eventNodes"].map{|event_node|
    [event_node, event_node["event"]["countryCode"], event_node["event"]["eventName"]]
  }.select{|_, country, event_name|
    ['US', 'GB'].include?(country) || event_name.include?(' @ ')
  }.map{|event, country, event_name|
    event["marketNodes"].select{|market|
      market["description"]["marketName"] == 'Moneyline'
    }.map{|market|
      [market["marketId"],country,event_name]
    }
  }
}.flatten(2)

require 'pp'
pp moneyline_market_ids
#=> [["1.128255531", "US", "Philadelphia @ Seattle"],
#   ["1.128272164", "US", "Arkansas @ Mississippi State"],
#   ["1.128255516", "US", "New England @ San Francisco"],
#   ["1.128272159", "US", "Indiana @ Michigan"],
#   ["1.128278718", "CA", "Edmonton @ Ottawa"],
#   ["1.128272176", "US", "Arizona State @ Washington"],
#   ["1.128272174", "US", "Alabama A&M @ Auburn"],
#    ...

edited May 23, 2017 at 10:32

CommunityBot

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answered Nov 20, 2016 at 20:16

Eric Duminil

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2 Comments

iamse7en Over a year ago

Thank you! I was so darn close to this on my own but kept getting a syntax error. Appreciate it.

iamse7en Over a year ago

Wow, that 2nd one could be really handy... thank you for going the extra mile!

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