title: Haskell filter by list index
body: <p>I have function:</p>
  
  <pre><code>isEven n = (mod n 2) == 0
  </code></pre>
  
  <p>And a I want only even numbers, I get:</p>
  
  <pre><code>filter isEven [1, 2, 3, 4 ,5 ,6] -- -&gt; 2, 4, 6
  </code></pre>
  
  <p>So far so  good.</p>
  
  <p>My question is: Is there in the function where I can filter by list index? (you can imagine js filter where second parameter is the index).</p>
  
  <p>If not is there any reason why this is not included and how can I do it in a good haskell way?</p>