title: Array filter in Swift3
body: <p>I have a piece of code. I am not getting whats going inside in this code. Can anybody explain it?</p>
  
  <pre><code> let wordFreqs = [("k", 5), ("a", 7), ("b", 3)]
  
          let res = wordFreqs.filter(
          {
              (e) -&gt; Bool in
  
              if e.1 &gt; 3 {
                  return true
              } else {
                  return false
              }
  
          }).map { $0.0 }
  
          print(res)
  </code></pre>
  
  <p>Gives Output: </p>
  
  <pre><code>["k","a"]
  </code></pre>