Reading and Writing YAML with jruby-complete.jar

data.yml

---
bubbles:
- xpos: 20
  ypos: 50
  diameter: 200
  emotion: happy
- xpos: 80
  ypos: 60
  diameter: 210
  emotion: sad
colors:
- xpos: 20
  ypos: 50
  diameter: 200
  colors: red
- xpos: 80
  ypos: 60
  diameter: 210
  colors: blue 

output.txt

{"xpos"=>20, "ypos"=>50, "diameter"=>200, "emotion"=>"happy"}
{"xpos"=>80, "ypos"=>60, "diameter"=>210, "emotion"=>"sad"}
{"xpos"=>20, "ypos"=>50, "diameter"=>200, "colors"=>"red"}
{"xpos"=>80, "ypos"=>60, "diameter"=>210, "colors"=>"blue"}

read_yaml.rb

require 'yaml'

data = YAML.load_file('data.yml')

data.fetch('bubbles').each do |bubble|
  puts bubble
end

data.fetch('colors').each do |bubble|
  puts bubble
end

write_yaml.rb

require 'yaml'

values1 = [20, 50, 200, 'happy']
values2 = [80, 60, 210, 'sad']
labels = %w[xpos ypos diameter emotion]
labels2 = %w[xpos ypos diameter colors]
data = [values1, values2].map { |entry| labels.zip(entry).to_h }
data2 = [values1, values2].map { |entry| labels2.zip(entry).to_h }
hash = { 'bubbles' => data, 'colors' => data2 }
open('data.yml', 'w') { |file| file.write(hash.to_yaml) }

Thank you! Extremely helpful example.