title: How do I find the index of an item in a vector?
body: <p>Any ideas what <code>????</code> should be? Is there a built in? 
  What would be the best way to accomplish this task?</p>
  
  <pre><code>(def v ["one" "two" "three" "two"])
  
  (defn find-thing [ thing vectr ]
    (????))
  
  (find-thing "two" v) ; ? maybe 1, maybe '(1,3), actually probably a lazy-seq
  </code></pre>