title: Pandas df.itertuples renaming dataframe columns when printing
body: <p>I know that normally pandas' itertuples() will return the values of each including the column names as follows:</p>
  
  <pre><code>ab=pd.DataFrame(np.random.random([3,3]),columns=['hi','low','med'])
  for i in ab.itertuples():
      print(i)
  </code></pre>
  
  <p>and the output is as follows:</p>
  
  <pre><code>Pandas(Index=0, hi=0.05421443, low=0.2456833, med=0.491185)
  Pandas(Index=1, hi=0.28670429, low=0.5828551, med=0.279305)
  Pandas(Index=2, hi=0.53869406, low=0.3427290, med=0.750075)
  </code></pre>
  
  <p>However, I have no idea why it doesn't shows the columns as I expected for my another set of code as below:</p>
  
  <pre><code>            us qqq equity  us spy equity
  date                                    
  2017-06-19            0.0            1.0
  2017-06-20            0.0           -1.0
  2017-06-21            0.0            0.0
  2017-06-22            0.0            0.0
  2017-06-23            1.0            0.0
  2017-06-26            0.0            0.0
  2017-06-27           -1.0            0.0
  2017-06-28            1.0            0.0
  2017-06-29           -1.0            0.0
  2017-06-30            0.0            0.0
  </code></pre>
  
  <p>the above is a Pandas Dataframe with Timestamp as index, float64 as the values in the list, and a list of string ['us qqq equity','us spy equity'] as the columns.</p>
  
  <p>When I do this:</p>
  
  <pre><code>for row in data.itertuples():
      print (row)
  </code></pre>
  
  <p>It shows the columns as _1 and _2 as follows:</p>
  
  <pre><code>Pandas(Index=Timestamp('2017-06-19 00:00:00'), _1=0.0, _2=1.0)
  Pandas(Index=Timestamp('2017-06-20 00:00:00'), _1=0.0, _2=-1.0)
  Pandas(Index=Timestamp('2017-06-21 00:00:00'), _1=0.0, _2=0.0)
  Pandas(Index=Timestamp('2017-06-22 00:00:00'), _1=0.0, _2=0.0)
  Pandas(Index=Timestamp('2017-06-23 00:00:00'), _1=1.0, _2=0.0)
  Pandas(Index=Timestamp('2017-06-26 00:00:00'), _1=0.0, _2=0.0)
  Pandas(Index=Timestamp('2017-06-27 00:00:00'), _1=-1.0, _2=0.0)
  Pandas(Index=Timestamp('2017-06-28 00:00:00'), _1=1.0, _2=0.0)
  Pandas(Index=Timestamp('2017-06-29 00:00:00'), _1=-1.0, _2=0.0)
  Pandas(Index=Timestamp('2017-06-30 00:00:00'), _1=0.0, _2=0.0)
  </code></pre>
  
  <p>Does anyone has any clue about what have I done wrong? Does it have to do with some variable referencing issue when creating the original dataframe? (Also, as a side question, I learnt from the community that the type of data generated from itertuples() should be tuples, but it seems (as shown above), the return type is  as I verified from the type statement?)</p>
  
  <p>Thank you for all your patience as I am still trying to master the application of DataFrame. </p>