title: Format double as 4+ digit String
body: <p>I have a <code>double</code> which contains values such as:</p>
  
  <ul>
  <li>19.52</li>
  <li>5.1</li>
  <li>6.13</li>
  <li>101.5</li>
  </ul>
  
  <p>It will not contain more than 2 fractional digits. That is being checked for. If there are more than 2, the rest can be ignored.</p>
  
  <p>I'd like to convert it to a <code>String</code> which has 4+ digits, like this:</p>
  
  <ul>
  <li>"1952"</li>
  <li>"0510"</li>
  <li>"0613"</li>
  <li>"10150"</li>
  </ul>
  
  <p>How can I do that?</p>
  
  <p>I'm using someone's API and the last 2 digits are specified as being always for the first 2 digits of the fractional part, that's why I need to do this.</p>