title: How do I use a ruby regex to get a substring?
body: <p>I want to get the numbers out of strings such as:  </p>
  
  <p><code>person_3<br>
  person_34<br>
  person_356<br>
  city_4<br>
  city_15</code><br>
  etc...</p>
  
  <p>It seems to me that the following should work:  </p>
  
  <p><code>string[/[0-9]*/]</code>  </p>
  
  <p>but this always spits out an empty string.  </p>