title: grouping by items in a list
body: <pre><code>&gt;&gt;&gt; with open('Book2.csv', 'rb') as f:
      inpreader = csv.reader(f, delimiter=',')
      for row in inpreader:
          print ','.join(row)
  
  IdNo, skillsList
  BAXA0000206_NEENA_TIWARI_0.htm,[u'Training', u'E-Learning', u'PowerPoint', u'Teaching', u'Accounting', u'Team Management', u'Team Building', u'Microsoft Excel', u'Microsoft Office', u'Financial Accounting', u'Microsoft Word', u'Customer Service']
  BAXA0000227_ABDUR_RAZZAQUE_0.htm,[u'Telecommunications', u'Data Center', u'ISO 27001', u'Management', u'BS25999', u'Technology', u'Information Technology...', u'Certified PMP\xae', u'Certified BS25999 Lead...']
  BAXA0000261_Priya _ Lobo_0.htm,[u'Market Research', u'Segmentation', u'Marketing Strategy', u'Consumer Behavior', u'Experience Working with...']
  </code></pre>
  
  <p>I want to find out the term frequency of each skill in skillsList.. How can I do it...</p>
  
  <p>Thanks</p>