Ruby code to parse and analyze social media stats in json format

Question

What do you think about this code I wrote. It reads several json files ( I attached them as pastebins) and the code outputs summary information calculated from the input.

# 1) calculate the
# engagement rate from the first JSON file (the user's Instagram media)
# - Calculate the average number of comments - Calculate the average
# number of likes - Calculate the engagement rate using (Average Likes +
# Average Comments)/# of Followers which is 435
# 
# 2) Combine the 2 sets of JSON data (Instagram media objects with their
# Instagram insights), then output a single JSON file where the insights
# are paired with their media objects in a clean format.
#
# Question 1.json: https://pastebin.com/V3Ue87H4
# Question2A.json: https://pastebin.com/YifXzimZ
# Question2B.json: https://pastebin.com/6X0JYXtD
require 'json'
input = JSON.parse( File.read('Question 1.json') )["data"]
avg_likes = input.map { |x| x["like_count"] }. inject{ |sum, el| sum + el }.to_f / input.size
avg_comments = input.map { |x| x["comments_count"] }.inject{ |sum, el| sum + el }.to_f / input.size
puts "Answer for Question 1: #{avg_likes + avg_comments / 435}\n\n"
input_a = JSON.parse( File.read('Question2A.json') )["data"]
input_b = JSON.parse( File.read('Question2B.json') ).map { |x| x["data"] }.flatten
output = input_a.map do |post|
 {
 :permalink => post["permalink"],
 :impressions => input_b.find { |x| x["id"] == "#{post['id']}/insights/impressions/lifetime" }["values"][0]["value"],
 :engagement => input_b.find { |x| x["id"] == "#{post['id']}/insights/engagement/lifetime" }["values"][0]["value"],
 :reach => input_b.find { |x| x["id"] == "#{post['id']}/insights/reach/lifetime" }["values"][0]["value"],
 :saved => input_b.find { |x| x["id"] == "#{post['id']}/insights/saved/lifetime" }["values"][0]["value"]
 }
end
puts "Answer for Question 2: " + JSON.pretty_generate(output)
# EXAMPLE OUTPUT - generated by running ruby coding_test.rb
#
# Answer for Question 1: 22.704827586206896
# 
# Answer for Question 2: [
# {
# "permalink": "https://www.instagram.com/p/B40LKjkAlDV/",
# "impressions": 236,
# "engagement": 33,
# "reach": 187,
# "saved": 2
# },
# {
# "permalink": "https://www.instagram.com/p/B4z4Vq5Ag5g/",
# "impressions": 212,
# "engagement": 22,
# "reach": 170,
# "saved": 0
# },
# {
# "permalink": "https://www.instagram.com/p/B4xnmtygmi-/",
# "impressions": 297,
# "engagement": 28,
# "reach": 218,
# "saved": 1
# },
# {
# "permalink": "https://www.instagram.com/p/B4uyfrLgjVi/",
# "impressions": 248,
# "engagement": 21,
# "reach": 194,
# "saved": 0
# },
# {
# "permalink": "https://www.instagram.com/p/B4nic12AFps/",
# "impressions": 292,
# "engagement": 15,
# "reach": 219,
# "saved": 0
# }
# ]

Answer 1

Good work.

Here are some points where you can improve:

• You can use input.sum { |x| x["like_count"] }.to_f instead of input.map { |x| x["like_count"] }.inject{ |sum, el| sum + el }
• It is a good idea to do calculations with BigDecimal instead of Float.
• 435 is a magic number, you can put it into a constant with a good name.
• The spaces before the parentheses aren't usual in the Ruby community style guide.
• Check the dig method available for Hash instances.
• You can use the new syntax for Hash instances when the keys are symbols: { hello: "world" }
• Use double-quotes or single-quotes, you're mixing both.