title: How do I design a class in Python?
body: <p>I've had some really awesome help on my previous questions <a href="https://stackoverflow.com/questions/4087919">for detecting paws</a> and <a href="https://stackoverflow.com/questions/3684484">toes within a paw</a>, but all these solutions only work for one measurement at a time.</p>
  
  <p><a href="http://dl.dropbox.com/u/5207386/RAR-collectie.rar" rel="noreferrer">Now I have data</a> that consists off:</p>
  
  <ul>
  <li>about 30 dogs; </li>
  <li>each has 24 measurements (divided into several subgroups); </li>
  <li>each measurement has at least 4 contacts (one for each paw) and 
  
  <ul>
  <li>each contact is divided into 5 parts and </li>
  <li>has several parameters, like contact time, location, total force etc.</li>
  </ul></li>
  </ul>
  
  <p><img src="https://i.stack.imgur.com/8x2uG.png" alt="alt text"></p>
  
  <p>Obviously sticking everything into one big object isn't going to cut it, so I figured I needed to use classes instead of the current slew of functions. But even though I've read Learning Python's chapter about classes, I fail to apply it to my own code (<a href="http://cloud.github.com/downloads/ivoflipse/DogsRus/pressureanalysis.py" rel="noreferrer">GitHub link</a>)</p>
  
  <p>I also feel like it's rather strange to process all the data <em>every</em> time I want to get out some information. Once I know the locations of each paw, there's no reason for me to calculate this again. Furthermore, I want to compare all the paws of the same dog to determine which contact belongs to which paw (front/hind, left/right). This would become a mess if I continue using only functions.</p>
  
  <p>So now I'm looking for advice on how to create classes that will let me process my data (<a href="http://dl.dropbox.com/u/5207386/Krupp_Krulle.rar" rel="noreferrer">link to the zipped data of one dog</a>) in a sensible fashion. </p>