title: How to access multi-level index in pandas data frame?
body: <p>I would like to call those row with same index.</p>
  
  <p>so this is the example data frame, </p>
  
  <pre><code>arrays = [np.array(['bar', 'bar', 'baz', 'baz', 'foo', 'foo', 'qux', 'qux']),
  np.array(['one', 'two', 'one', 'two', 'one', 'two', 'one', 'two'])]
  
  df = pd.DataFrame(np.random.randn(8, 4), index=arrays)
  
  In [16]: df
  Out[16]: 
                  0         1         2         3
  bar one -0.424972  0.567020  0.276232 -1.087401
      two -0.673690  0.113648 -1.478427  0.524988
  baz one  0.404705  0.577046 -1.715002 -1.039268
      two -0.370647 -1.157892 -1.344312  0.844885
  foo one  1.075770 -0.109050  1.643563 -1.469388
      two  0.357021 -0.674600 -1.776904 -0.968914
  qux one -1.294524  0.413738  0.276662 -0.472035
      two -0.013960 -0.362543 -0.006154 -0.923061
  </code></pre>
  
  <p>I would like to select </p>
  
  <pre><code>                0         1         2         3
  bar one -0.424972  0.567020  0.276232 -1.087401
  baz one  0.404705  0.577046 -1.715002 -1.039268
  foo one  1.075770 -0.109050  1.643563 -1.469388
  qux one -1.294524  0.413738  0.276662 -0.472035
  
  </code></pre>
  
  <p>or even as this format</p>
  
  <pre><code>            0         1         2         3
  one -0.424972  0.567020  0.276232 -1.087401
  one  0.404705  0.577046 -1.715002 -1.039268
  one  1.075770 -0.109050  1.643563 -1.469388
  one -1.294524  0.413738  0.276662 -0.472035
  
  </code></pre>
  
  <p>I have tried <code>df['bar','one]</code> and it's not working. I am now sure how should I access the multi-level index.</p>