title: How to iterate backwards in a for loop with a range
body: <p>In the default case in this switch statement, I'm trying to iterate backwards in a for loop, there are examples of how to do this when working with Int's but I haven't found any with variables.</p>
  
  <pre><code>func arrayLeftRotation(myArray: [Int], d:Int) {
          var newArray = myArray
          switch d {
          case 1:
              let rotationValue = newArray.removeLast()
              newArray.insert(rotationValue, at: 0)
  
          default:
              let upperIndex = newArray.count - 1
              let lowerIndex = newArray.count - d
              for i in lowerIndex...upperIndex {
                  let rotationValue = newArray.remove(at: i)
                  newArray.insert(rotationValue, at: 0)
              }
          }
          print(newArray)
      }
  </code></pre>
  
  <p>So I wish to count down from <code>upperIndex to lowerIndex</code></p>