regex masking patterns
<p>I have these inputs:</p>



<pre class="lang-none prettyprint-override"><code>DFDBDFDFDF21R123
DFDBDFDFDF34R123
</code></pre>

<p>I want to match these inputs, except positions 9 and 10, like below:</p>

<pre class="lang-none prettyprint-override"><code>DFDBDFDFxxR123
DFDBDFDFxxR123
</code></pre>

<p>So, to be clear: match 1-8, exclude 9-10, match 11-16.</p>