title: Parse CSV file and modify columns
body: <p>I'd like to change a CSV file in a specific way. This is my sample CSV file:</p>
  
  <pre><code>name,time,Operations
  Cassandra,2015-10-06T15:07:22.333662984Z,INSERT
  Cassandra,2015-10-06T15:07:24.334536781Z,INSERT
  Cassandra,2015-10-06T15:07:27.339662984Z,READ
  Cassandra,2015-10-06T15:07:28.344493608Z,READ
  Cassandra,2015-10-06T15:07:28.345221189Z,READ
  Cassandra,2015-10-06T15:07:29.345623750Z,READ
  Cassandra,2015-10-06T15:07:31.352725607Z,UPDATE
  Cassandra,2015-10-06T15:07:33.360272493Z,UPDATE
  Cassandra,2015-10-06T15:07:38.366408708Z,UPDATE
  </code></pre>
  
  <p>I know how to read from CSV file using python parser but I'm totally a beginner with that. I need to get such an output:</p>
  
  <pre><code>start_time,end_time,operation
  2015-10-06T15:07:22.333662984Z,2015-10-06T15:07:24.334536781Z,INSERT    
  2015-10-06T15:07:27.339662984Z,2015-10-06T15:07:29.345623750Z,READ
  2015-10-06T15:07:31.352725607Z,2015-10-06T15:07:38.366408708Z,UPDATE
  </code></pre>
  
  <p><strong>Comment:</strong>
  The start time is a timestamp given at beginning of specific query (insert/read,update) and accordingly the end time is completion of the query.  </p>
  
  <p>Thanks.</p>