title: What does _ and .. mean in a for loop?
body: <p>I'm doing the <a href="https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/GuidedTour.html" rel="nofollow noreferrer">A Swift Tour</a>.</p>
  <p><em>One:</em></p>
  <p>I'm not getting the <code>Generics</code> functions logic. Its for <code>Design Patterns</code>? And the explanation on the tour looks very short and unclear.</p>
  <p><em>Two:</em></p>
  <p>In this pice of code for creating a generic function,</p>
  <pre><code>func repeatItem&lt;Item&gt;(item: Item, numberOfTimes: Int) -&gt; [Item] {
      var result = [Item]()
      for _ in 0..&lt;numberOfTimes { //im not getting this line (?)
          result.append(item)
      }
      return result
  }
  repeatItem(&quot;knock&quot;, numberOfTimes:4)
  </code></pre>
  <p>I do not understand this syntax very well, what means <code>_</code>, <code>..</code>, and <code>&lt;</code> in the same line, why is used?</p>