Create Yaml without file

Question

For some dark reasons, I have to convert a specific formated array to hash and a solution was to go through YAML.

I didn't reach to convert an array to hash through yaml without creating a file, could you help me ?

My Original Array could be like this one :

[
  ["lvl1"],
  [nil,"lvl2"],
  [nil, nil, "lvl3", "value1", "value2", "value3"],
  [nil, "lvl2bis"],
  [nil, nil, "lvl3bis", "value1bis", "value2bis", "value3bis"]
]

I transform this Array to string:

• For a string

  yml_text = []
  array.each do |line|
    yml_line = line.join(",").gsub(/\G,/, '  ').sub(/,+\z/, ']').sub(/:,+/, ':  [')
    yml_text << yml_line
  end
  yml_text = yml_text.join("\n")
  

• For a file

  f = File.open(yml_file_path, "w")
  array.each do |line|
    yml_line = line.join(",").gsub(/\G,/, '  ').sub(/,+\z/, ']').sub(/:,+/, ':  [')
    f.puts(yml_line)
  end
  f.close
  

I got the following result:

lvl1:
  lvl2:
    lvl3: ["value1", "value2", "value3"]
  lvl2bis:
    lvl3bis: ["value1", "value2", "value3"]

If I save this text in a yml file and parse it like this:

hash = YAML.load(File.read(yml_file_path)) 

I got my hash:

{ "lvl1" => {
    "lvl2" => {
      "lvl3" => ["value1", "value2", "value3"]
    },
    "lvl2bis" => {
      "lvl3bis" => ["value1bis", "value2bis", "value3bis"]
    }
  }
}

If I do not save this text as yml file and try to load my yml_text, I obtain this :

yml_data = YAML.load(yml_text)
p yml_data
"lvl1 lvl2 lvl3,value1,value2,value3 lvl2bis lvl3bis,value1bis,value2bis,value3bis"

Is it impossible to go through YAML without creating a file ?

Answer 1

This doesn't answer your YAML question as such, just converts the array directly into a hash:

def to_hash(array)
  default = ->(hash, key) { hash[key] = Hash.new(&default) }
  keys = []
  array.inject(Hash.new(&default)) do |hash, element|
    compacted = element.compact
    if compacted.length > 1
      nested_hash = keys.inject(hash) { |sub_hash, key| sub_hash[key] }
      nested_hash[compacted.shift] = compacted
    else
      keys = keys.take(element.count(nil))
      keys[keys.length] = compacted.shift
    end
    hash
  end
end

Answer 2

YAML.load(
  inp.map(&:dup).map do |a| # #dup is required for safe #shift below
    count, arr = (0...a.size).each do |i|
      curr = a.shift
      break [i, curr] unless curr.nil?
    end
    "  " * count << arr << ": " << (a.empty? ? "" : a.inspect)
  end.join($/)
)
#⇒ {"lvl1"=>{"lvl2"=>{"lvl3"=>["value1", "value2", "value3"]},
#     "lvl2bis"=>{"lvl3bis"=>["value1bis", "value2bis", "value3bis"]}}}