title: Get Number Grouping with Regex
body: <p>I have strings that look like this:</p>
  
  <pre><code>get_a_string_A14_for_1.23.87.19_A12_and_others
  get_a_string_A14_for_1.23.827.19_A12_and_others
  get_a_string_A14_for_1.23.87.1_A12_and_others
  get_a_string_A14_for_2.23.87.19_A12_and_others
  </code></pre>
  
  <p>I want to pull the numbers <code>1.23.87.19</code>, <code>1.23.827.19</code>, <code>1.23.87.1</code>, and <code>2.23.87.19</code>. The numbers will change, but this is the basic structure of the numbers. </p>
  
  <p>I have tried doing:</p>
  
  <pre><code>([0-9]\.[0-9])
  [0-9]\.[0-9]{1,4}
  [0-9]\.[0-9]\.[0-9]{1,4}
  [0-9]\.[0-9]\.[0-9]
  </code></pre>
  
  <p>And more, but have not had any luck. Can someone please help, and explain what I need to do to get these number groupings? </p>