title: Is there a "reverse" function for d3.format?
body: <p>I'm searching for a reverse function for </p>
  
  <p><code>d3.format(".3s")</code> (1)</p>
  
  <p><a href="https://github.com/d3/d3-format" rel="nofollow noreferrer">function</a> with no success.</p>
  
  <p>This function (1) get a number and format it using <a href="https://en.wikipedia.org/wiki/Metric_prefix" rel="nofollow noreferrer">metric prefix</a></p>
  
  <p>examples:</p>
  
  <pre><code>var f = d3.format(".3s");
  f(42000); // "420k"
  f(0.0042); // "4,20µ"
  </code></pre>
  
  <p>What i want is a function that does the reverse: <strong>get a string with metric prefix and return a number</strong></p>
  
  <p>I'm not asking for a possible implementation, but if you have some, it is welcome. I'm asking if there is something already done in d3.
  I searched for it in d3 and found nothing. </p>