title: How to add every nth entry in a python list to each other?
body: <p>Let's say I have a python list:     </p>
  
  <pre><code>[4,5,25,60,19,2]
  </code></pre>
  
  <p>How can I add every nth entry to each other?</p>
  
  <p>e.g. I split the list into 3 entries [ 4,5 / 25,60 / 19,2 ], then add these entries in order to get a new list:</p>
  
  <pre><code>[4+25+19, 5+60+2]
  </code></pre>
  
  <p>Which gives me the sum:</p>
  
  <pre><code>[48, 67]
  </code></pre>
  
  <p>For a more complex example, lets say I have 2000 entries in my list. I want to add every 100th entry to the one before so I get 100 entries in the new list. Each entry would now be the sum of every 100th entry.</p>