title: Biopython PDB: get resseq
body: <p>I've parsed from a pdb file a list of residues:</p>
  
  <pre><code>res_list=PDB.Selection.unfold_entities(Find_chain(par), 'R')
  </code></pre>
  
  <p>(Find_chain is a function that selects the chain I need), and i'm doing a loop on all the residues, calculating a specific factor for every one. But I also need the "resseq" (because, if I understood, it is the number of the residue as reported in the pdb file). If I do </p>
  
  <pre><code>for residue in res_list:
     print residue
  </code></pre>
  
  <p>I get</p>
  
  <pre><code>&lt;Residue SER het=  resseq=1 icode= &gt;
  &lt;Residue GLN het=  resseq=2 icode= &gt;
  &lt;Residue ALA het=  resseq=3 icode= &gt;...
  </code></pre>
  
  <p>but I can't find an function to access the number after "resseq". I know I can manipulate the string, but I wonder if there is a Biopython function to get it somehow!!
  Thank you!</p>