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

Here is another approach :

def get_all_keys(h)
  h.each_with_object([]){|(k,v),a| v.is_a?(Hash) ? a.push(k,*get_all_keys(v)) : a << k }
end

hash = {"a" => 1, "b" => {"c" => {"d" => 3}}}
p get_all_keys(hash)
# >> ["a", "b", "c", "d"]