title: python re match string in a file
body: <p>I want to match all the lines in a file either starting with <code>0D</code> and has 15 <code>Characters</code> or just having 15 digits. How  can i do this</p>
  
  <pre><code>p_number = re.compile(r'(\d{15})')
  f=open(infile)
  for l in f:
    aa=re.findall(p_number,l)
    if aa &gt; 0:
       print aa
  f.close() 
  </code></pre>
  
  <p><code>EDIT</code></p>
  
  <p>If only the pattern is in the starting of the line.</p>