title: How to swap keys and values in a hash
body: <p>How do I swap keys and values in a Hash?</p>
  
  <p>I have the following Hash:</p>
  
  <pre><code>{:a=&gt;:one, :b=&gt;:two, :c=&gt;:three}
  </code></pre>
  
  <p>that I want to transform into:</p>
  
  <pre><code>{:one=&gt;:a, :two=&gt;:b, :three=&gt;:c}
  </code></pre>
  
  <p>Using <code>map</code> seems rather tedious. Is there a shorter solution?</p>