title: NSURL "missing argument for parameter in call" Swift
body: <p>I use obj-c and swift classes together. And at one swift class, I try to convert objective c code to swift. However, I have a problem about NSURL.</p>
  
  <p>the original code is:</p>
  
  <pre><code>NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"%@://", appItem.URLSchema]];
  </code></pre>
  
  <p>and URLSchema is declared in the header file like this:</p>
  
  <pre><code>@property (nonatomic, copy) NSString *URLSchema;
  </code></pre>
  
  <p>I convert the objective c code which is above to swift:</p>
  
  <pre><code>var url: NSURL = NSURL(string:"%@://",relativeToURL: appItem.URLSchema)
  </code></pre>
  
  <p>but it says "missing argument for parameter "path" in call"</p>
  
  <p>when I try this:</p>
  
  <pre><code>var url: NSURL = NSURL.URLWithString("%@://", appItem.URLSchema)
  </code></pre>
  
  <p>it says extra argument in call.</p>
  
  <p>what do you suggest to convert it properly?</p>