How do I find keys in my hash to map to elements that match a condition?

Question

I have a hash that maps integers to arrays. For example

{1 => [\"abc\"], 2 => [\"ccc\", \"ffffd\"]}

How do I get all the keys from my hash

Answer 1

Anything like this?

hash.each_key.select { |key| hash[key].count >= 2 }