title: Regex: At least one uppercase char, one lowercase char, one digit and nothing else
body: <p>I would to have a regex for password matching to make sure password contains: </p>
  
  <ol>
  <li>at least one digit </li>
  <li>at least one uppercase alphabet</li>
  <li>at least one lowercase alphabet</li>
  <li>nothing else (only digits and numbers)</li>
  </ol>
  
  <p>size is at least 6 and at most 15 characters</p>
  
  <p>I tried this regex <code>^(?=.*?[A-Z])(?=.*?[a-z])(?=.*?[0-9]).{6,15}$</code> but it doesn't apply check #4 and matches a password that includes a special character, too. </p>
  
  <p>Some other questions are available that address the question for abscense of some explicit letters. As you can see in the answer I accepted, the regex is not close to what I was looking for. </p>