title: About underscore.map
body: <p>I have the following object  </p>
  
  <pre><code>{one : 1, two : 2, three : 3}
  </code></pre>
  
  <p>and I would like </p>
  
  <pre><code>[1,2]
  </code></pre>
  
  <p>Here my code</p>
  
  <pre><code>_.map({one : 1, two : 2, three : 3}, function(num, key){ 
           if (key==='one' || key==='two') {
               return num;
           } 
  }); // [1, 2, undefined]
  </code></pre>
  
  <p>Actually I would like <code>[1,2]</code></p>
  
  <p>How can I improve my code?<br>
  thanks</p>