title: Extract a 8 digit number from string of variable size
body: <p>I have a string of undetermined size which contains a 8 digit number. Example:</p>
  
  <pre><code>This is 123456 a string
  This is a new string 123456
  123456 This is another string
  </code></pre>
  
  <p>How can I extract the integer value of such number?</p>