title: regular expression: r05c75 -- extracting numbers between bookends
body: <p>Today, I am learning regular expressions =D</p>
  
  <p>I understand some basics, like <code>\d+</code> matches any number of digits, but how would I get the values after 'r' and 'c' in the string <code>r05c75</code> (the numbers are arbitrary length)</p>
  
  <p>They represent row and column values and I want to extract the number between 'r' and 'c' and the number between 'c' and $ (end-of-string).</p>
  
  <p>I'm hoping this question will also be elucidative for any other beginners as well.</p>
  
  <p>The general case would be </p>
  
  <pre><code>aaa DDD bbb DDD ccc DDD (without spaces)
  </code></pre>
  
  <p>where aaa, bbb, ccc, and ddd are arbitrary (known) strings, and the D-triplets are just digits.</p>
  
  <p>I can "match" (check the validity) of my string r05c75, but I am not sure how to extract the numbers.</p>
  
  <p>This is probably a fairly common question, I'm sorry if I missed any duplicates.</p>