Hash merges in Ruby for dmolchan

main.rb

require 'pp' # gives us prety printing

users = {} # will be a map of GitHub user name to user info

# Add Aren to the map
users[:aren55555] = {
  name:     "Aren Patel",
  company:  "BufferBox -> Google -> Nest",
  location: "Narnia",
  website:  "https://arenpatel.com"
}

# Add Dima to the map
users[:dmolchan] = {
  name:     "Dmitriy Molchan",
  company:  "Nest",
  location: "San Jose, California",
  website:  nil
}

puts "Users map: \n#{users.pretty_inspect}\n" # prints the map - cool!

others = {}  # will be a map of similar structure

# Add Sam to this map
others[:shwoodard] = {
  name:     "Sam Woodard",
  comapny:  "Google",
  location: "Woodside, California",
  website:  nil,
  repos: ["google/jsonapi", "shwoodard/sprites"]
}

puts "Others map: \n#{others.pretty_inspect}\n" # prints the map - neato!

merger1 = users.merge(others) # merges others on top of users, and creates a new map

puts "Merger1 map: \n#{merger1.pretty_inspect}\n" # prints the map - sweet!

# Add Aren to the others map
others[:aren55555] = {
  repos: ["google/jsonapi", "AMFDPMTE/list"]
}

users.merge!(others) # merges others into users

puts "Users map: \n#{users.pretty_inspect}\n" # prints the map - sweet!
# note: that all the keys (:name, :company, :location, :website) from
#       users[:aren55555] were overwrittien by the keys (just :repos) from
#       others[:aren5555]. In summary a.merge(b) or a.merge!(b) are just
#       overwritting the intersecting (common) values in a with the values from
#       b. The non intersecting keys/values from a and b will be present in the
#       resultant hash.
#
#       Hash#merge  http://ruby-doc.org/core-2.0.0/Hash.html#method-i-merge
#       Hash#merge! http://ruby-doc.org/core-2.0.0/Hash.html#method-i-merge-21