title: Clojure way of for...in
body: <p>What is the clojure way of for...in ?
  Say I am doing some job like(maybe)</p>
  
  <pre><code>for key in map.keys do
      FUNC(key)
  end
  </code></pre>
  
  <p>to construct a new map, using key of map as new map's key, and some return values as new map's value.</p>