title: Ruby: Deleting all instances of a particular key from hash of hashes
body: <p>I have a hash like</p>
  
  <pre>
  h = {1 => {"inner" => 45}, 2 => {"inner" => 46}, "inner" => 47}
  </pre>
  
  <p>How do I delete every pair that contains the key "inner"?<br>
  You can see that some of the "inner" pairs appear directly in <code>h</code> while others appear in pairs in <code>h</code></p>
  
  <p>Note that I only want to delete the "inner" pairs, so if I call my mass delete method on the above hash, I should get</p>
  
  <pre>h = {1 => {}, 2 => {}}</pre>
  
  <p>Since these pairs don't have a key == "inner"</p>