title: Convert fullwidth string into halfwidth string
body: <p>How can I convert <code>Ａb９８７６５４３２１０</code> into <code>Ab9876543210</code>? Is there a solution by regular expression?</p>
  <p><code>test &lt;- dput(&quot;Ａb９８７６５４３２１０&quot;)</code></p>