title: create a tuple from columns in a pandas DataFrame
body: <p>I would like to automatically create a tuple (to be passed to a scipy.stats function) from columns in a pandas dataframe, so that each row of the tuple are the values from each column of the dataframe.
  here is the header from my dataframe:</p>
  
  <pre><code>                     4_3-a-0    5_3-a-4    7_3-a-3
  datetime_pac                                      
  2015-09-03 22:00:00   -100.4 -96.857143 -55.000000
  2015-09-03 22:01:00   -100.5 -91.700000 -55.600000
  2015-09-03 22:02:00   -100.4 -90.875000 -55.900000
  2015-09-03 22:03:00   -100.4 -94.000000 -55.555556
  2015-09-03 22:04:00   -100.5 -99.500000 -55.545455
  </code></pre>
  
  <p>I can achieve this manually like so:</p>
  
  <pre><code>from scipy import stats
  stats.f_oneway(df.ix[:,0], df.ix[:,1], df.ix[:,2])
  </code></pre>
  
  <p>But I would like to 'automate' it in cases where the number of columns in the dataframe is unknown. The following attempts (and many variations of) would not work:</p>
  
  <pre><code>stats.f_oneway(tuple(x) for x in xtmp.values)
  stats.f_oneway((xtmp[x]) for x in xtmp.columns)
  </code></pre>
  
  <p>Thanks for your help!</p>