title: Extracting speciific string in Python
body: <p>I have log file in wich at some point I added timestam creation and now it look like this:<br>
  <code>log.txt:</code></p>
  
  <pre><code>327555
  327563
  327570
  327601
  2012-11-19 22:21:37 :: 327001
  2012-11-19 22:21:37 :: 327004
  2012-11-19 22:21:37 :: 327007
  2012-11-19 22:21:37 :: 327008
  </code></pre>
  
  <p>In my Python script i used to read all lines from log.txt and add it line-by-line to a set for futher usage:</p>
  
  <pre><code>log_file = open('log.txt')
  set_log = set([])
  for line in log_file:
      set_log.add(line.strip())
  log_file.close()
  </code></pre>
  
  <p>But since timestam was added this solution and gives me wrong values in my set ( it includes timestam as well).</p>
  
  <p>Q: How to make it more flexible, so it udersteads lines without timestams and WITH timestams and extract only proper values? </p>