title: Update elements of a list
body: <p>Why aren't the elements updated within the for-loop? This gets me</p>
  
  <pre><code>met_dir = r'D:\09052012\run\fout'
  out_dir = r'D:\inpassingstest\test_cmd'
  
  for c_dir in [met_dir,out_dir]:
      if c_dir[-1:] != '\\':
         c_dir += '\\'
         print c_dir
  print met_dir
  
  &gt;&gt;&gt;D:\09052012\run\fout\
  &gt;&gt;&gt;D:\inpassingstest\test_cmd\
  &gt;&gt;&gt;D:\09052012\run\fout
  </code></pre>
  
  <p>Same happens when I use a index to address the elements. </p>