Ruby: Get all keys in a hash (including sub keys)

Question

let\'s have this hash:

hash = {\"a\" => 1, \"b\" => {\"c\" => 3}}
hash.get_all_keys 
=> [\"a\", \"b\", \"c\"]

how can i get all key

Answer 1

Also deal with nested arrays that include hashes

def all_keys(items)
  case items
  when Hash then items.keys + items.values.flat_map { |v| all_keys(v) }
  when Array then items.flat_map { |i| all_keys(i) }
  else []
  end
end