title: Why i am not able to pass optional value ( ? ) for getting image url?
body: <pre><code>self.imgView .sd_setImageWithURL(NSURL(string: dictData["image"] as? String))
  </code></pre>
  
  <p>Hello I am using swift and I want to get image URL from dictData but when I Write this line</p>
  
  <p><code>dictData["image"] as? String</code>  </p>
  
  <p>it's giving error like this <code>Value of optional type 'String?' not unwrapped; did you mean to use '!' or '?'?</code> and when I click on the error its improve my line of code by this</p>
  
  <p><code>dictData["image"] as! String</code></p>
  
  <p>Why this happened? I want to know the  reason behind that.   </p>