R regular expression to parse call option code : <p>I have a call option code in the form of:</p>

<p><code>.TSLA181012C100</code></p>

<p>I'd like to parse it to pull out the 18, 10 and 12. However, I'm not quite sure how to do that as the letters after the period can be of variable length and so can the numbers after the C. </p>

<p>Is there a regex way to find the "C" from the right and get the 6 digits to the left of that?</p>
