title: How works this expression for transform mac int48bits to hex? PYTHON
body: <p>Hello can anybody explain me how works this expression for transform a <code>getnode()</code> result in python to an hex standard format mac address?</p>
  
  <pre><code>import re, uuid
  print ':'.join(re.findall('..', '%012x' % uuid.getnode()))
  </code></pre>
  
  <p>I cant understand what is the <code>%012x</code> and why transform the <code>getnode()</code>.</p>
  
  <p>Please help  and thanks</p>