title: Regex for double numbers in dart
body: <p>As from my previous question I'm trying to allow only numbers in double format into a TextField. I have looked through the whole wide web and didn't find a Regex for dart.</p>
  
  <pre><code>TextFormField(
          inputFormatters: [
            WhitelistingTextInputFormatter(RegExp(r'\d*\.?\d+')) //&lt;-- useless attempt to allow double digits only
          ])
  </code></pre>