title: python del not freeing all the memory
body: <p>In my python program, I use <code>pandas</code> to read a csv file and store in memory:</p>
  
  <pre><code>data = pandas.read_csv('data.csv')
  </code></pre>
  
  <p>Before running the above command I check the free memory with <code>free -m</code> and the output is <code>1704</code>. After running the above command the output is <code>729</code>. I run</p>
  
  <pre><code>del(data)
  </code></pre>
  
  <p>to free the memory used by <code>data</code>. Now when I check the free memory the output is <code>1093</code> which is much less than the original <code>1704</code>. Where did the rest go? How can I free it? I'm running all these in <code>ipython</code> and even exiting ipython doesn't free up that memory.</p>
  
  <p>Thanks.</p>