title: Python: fastest way to retrieve comma-separated data in a file
body: <p>I have a file of a couple hundred thousand lines which looks like this:</p>
  
  <pre><code>01,T,None,Red,Big
  02,F,None,Purple,Small
  03,T,None,Blue,Big
  .......
  </code></pre>
  
  <p>I want something that will retrieve the <em>n</em> th column from the whole file. For example, the 4th column would be:</p>
  
  <pre><code>Red
  Purple
  Blue
  </code></pre>
  
  <p>Since the file is very big, I am interested in knowing the most efficient way to do this.</p>
  
  <p>The obvious solution would be to go through the file line by line, then apply split(',') and get the 4th item in the array, but I am wondering if there is anything slightly better.</p>