如何在ruby哈希中获取密钥的一部分

Question

如何从看起来像这样的哈希中获取1？

{{1=>2} => 3}

Answer 1

{{1=>2} => 3}.keys
#=> [{1=>2}]

{{1=>2} =>3 }.keys[0]
#=> {1=>2}

{{1=>2}=>3}.keys[0].keys
#=> [1]

{{1=>2}=>3}.keys[0].keys[0]
#=> 1

Answer 2

{{1=>2}=>3}.keys.first.keys.first