title: Does Scala have any collections that sort by value instead of key?
body: <p>For example the following code produces the order Stock1, Stock2, Stock3</p>
  
  <pre><code>var tm = TreeMap("Stock1" -&gt; 4.2, "Stock3" -&gt; 3.7, "Stock2" -&gt; 5.9)
  </code></pre>
  
  <p>What I'm looking for is a collection or technique that can produce the following</p>
  
  <p>Stock2, Stock1, Stock3 which represents the prices in descending order</p>