title: Filter large csv files (10GB+) based on column value in Python
body: <p><strong>EDITED : Added Complexity</strong></p>
  
  <p>I have a large csv file, and I want to filter out rows based on the column values. For example consider the following CSV file format:</p>
  
  <pre><code>Col1,Col2,Nation,State,Col4...
  a1,b1,Germany,state1,d1...
  a2,b2,Germany,state2,d2...
  a3,b3,USA,AL,d3...
  a3,b3,USA,AL,d4...
  a3,b3,USA,AK,d5...
  a3,b3,USA,AK,d6...
  </code></pre>
  
  <p>I want to filter all rows with <code>Nation == 'USA'</code>, and then based on each of the 50 state. What's the most efficient way of doing this? I'm using Python. Thanks</p>
  
  <p>Also, is R better than Python for such tasks?</p>