title: update/change array value (swift)
body: <p><strong>Data Model</strong></p>
  
  <pre><code>class dataImage {
      var userId: String
      var value: Double
      var photo: UIImage?
      var croppedPhoto: UIImage?
  
  init(userId:String, value: Double, photo: UIImage?, croppedPhoto: UIImage?){
      self.userId = userId
      self.value = value
      self.photo = photo
      self.photo = croppedPhoto
     }
  
  }
  </code></pre>
  
  <p><strong>View Controller</strong></p>
  
  <pre><code>var photos = [DKAsset]() //image source
  var datas = [dataImage]()
  
  var counter = 0
      for asset in photos{
          asset.fetchOriginalImageWithCompleteBlock({ image, info in // move image from photos to datas
  
              let images = image
              let data1 = dataImage(userId: "img\(counter+1)", value: 1.0, photo: images, croppedPhoto: images)
              self.datas += [data1]
              counter++
  
          })
      }
  </code></pre>
  
  <p>from that code, let's say i have 5 datas:</p>
  
  <pre><code> - dataImage(userId: "img1", value: 1.0, photo: images, croppedPhoto:
     images)
   - dataImage(userId: "img2", value: 1.0, photo: images, croppedPhoto:
     images)
   - dataImage(userId: "img3", value: 1.0, photo: images, **croppedPhoto:
     images**)
   - dataImage(userId: "img4", value: 1.0, photo: images, croppedPhoto:
     images)
   - dataImage(userId: "img5", value: 1.0, photo: images, croppedPhoto:
     images)
  </code></pre>
  
  <p>How to change/update img3's <strong>croppedImage</strong> value?</p>