title: Get the key of a hash with a partial array value
body: <p>I am trying to get the key of a hash by matching against an array. Here is my hash:</p>
  
  <pre><code>hash = {
     "My Key" =&gt; ["a", "b", "c"]
  }
  </code></pre>
  
  <p>I can run the following code and get the key "My Key".</p>
  
  <pre><code>hash.key(["a", "b", "c"])
  </code></pre>
  
  <p>However, I want to be able to get the key by only supplying a portion of the array like this:</p>
  
  <pre><code>hash.key("a") #should return "My Key"
  </code></pre>
  
  <p>Is this possible with <code>.key</code>? If not, how can I achieve this? Thanks in advance. </p>