TIL: Automatic Deep Keys with Ruby Hashes

Generate keys automatically for building deep hashes quickly. Best explained with an example:

hash = {}
hash[:person][:name][:given] = 'Billy'
# NoMethodError (undefined method `[]=' for nil:NilClass)

Set the default hash value using a bit of proc magic:

hash = Hash.new { |hash,key| hash[key] = Hash.new(&hash.default_proc) }
hash[:person][:name][:given] = 'Billy'
# {:person=>{:name=>{:given=>"Billy"}}}