Is auto-initialization of multi-dimensional hash array possible in Ruby, as it is in PHP? [duplicate]

Answer 1

Since 2014 there is also Gem XKeys for nested arrays, hashes, and potentially other objects.

Answer 2

Try this:

def hash_with_default_hash
    Hash.new { |hash, key| hash[key] = hash_with_default_hash }
end

a = hash_with_default_hash

If the key doesn't exist, then the result of the block will be used as the default value. In this case, the default value is also a hash which uses hashes as its default values.