title: pyspark operations on datasets
body: <p>I recently started learning pySpark for network graph manipulation. I'm still trying to grasp how spark works using dataframes.</p>
  <p>From what I understand:</p>
  <ol>
  <li><p>Data in dataframes are distributed (the same way they are distributed with hadoop) on a cluster of machines.</p>
  </li>
  <li><p>Operations on dataframes are distributed the same way (or ,in my case, locally using a given number of threads) .</p>
  </li>
  </ol>
  <p>My main question is: Are only operations on dataframes distributed or all operations (lets say on python's dictionaries) distributed once they are executed in pyspark's shell?</p>
  <p>Any further clarifications or articles are appreciated.</p>