title: how to extract token from string in python?
body: <p>I'm pretty new to Python and I know Perl can do this, but I haven't found it in Python yet.
  What I'm trying to do is to extract a token from a line.  </p>
  
  <pre><code>p = re.compile('555=\d+')
  ID = p.findall(line)
  </code></pre>
  
  <p>where line is a single line in a file, and the digits after 555= should be recorded. However, with these two lines, I can only get things like 555=1234567, what I really want is 1234567. Can anyone help and suggest a solution?
  Thanks!</p>