title: Convert NSString to Int and then use that value to determine which text to display in a UILabel
body: <p>I have my weather station app I am working on, it all works but the one thing I want to do is with the UV rating there is usually and word rating associated with the number. (Ex - UV rating is less then 3, word accompniing it "Low", between 3-6, "Medium" and etc...) 
  How do I convert my NSString, which displays the value into and int and then assign a word based on the range in which that value falls in.</p>
  
  <p>I know how I would do the comparing in Java but I do not know how to in swift.
  This is what I was thinking for it ( sudocode, Java basedish):</p>
  
  <pre><code>METHOD()
  if(this.UVrating() &lt; 3)
  println("Low")
  </code></pre>
  
  <p>First of course I need to convert the NSString to an int in order to do this. The NSString will always be an integer.</p>
  
  <p>TL;DR - </p>
  
  <p>1: Convert NSString to int</p>
  
  <p>2: Depending on int value, update a UILabel with "Low" "Medium" "High" and "Extreme"</p>
  
  <p>Low -> 0-3</p>
  
  <p>Medium -> 4-6</p>
  
  <p>High -> 7-10</p>
  
  <p>Extreme -> 11+</p>