title: extracting a substring between two slash characters of an NSString representing a URL
body: <p>I have an NSString object which is the URL of a webpage that contains a long random group of characters.  I want to extract the characters contained between the only two slashes in the string.  Can anybody help me to do this?  For example, I would like to extract the sting between somewebpage.com and nextlink in the following string.</p>
  
  <p><a href="https://somewebpage.com/687474703a2f2f696e74726163782e636174686179706163696669632e636/nextlink/home" rel="nofollow">Link</a>.</p>