title: Pandas dataframe as input for matplotlib.pyplot.boxplot
body: <p>I have a pandas dataframe which looks like this:</p>
  
  <pre><code>[('1975801_m', 1      0.203244
  10    -0.159756
  16    -0.172756
  19    -0.089756
  20    -0.033756
  23    -0.011756
  24     0.177244
  32     0.138244
  35    -0.104756
  36     0.157244
  40     0.108244
  41     0.032244
  42     0.063244
  45     0.362244
  59    -0.093756
  62    -0.070756
  65    -0.030756
  66    -0.100756
  73    -0.140756
  77    -0.110756
  81    -0.100756
  84    -0.090756
  86    -0.180756
  87     0.119244
  88     0.709244
  102   -0.030756
  105   -0.000756
  107   -0.010756
  109    0.039244
  111    0.059244
  Name: RTdiff), ('3878418_m', 1637    0.13811
  1638   -0.21489
  1644   -0.15989
  1657   -0.11189
  1662   -0.03289
  1666   -0.09489
  1669    0.03411
  1675   -0.00489
  1676    0.03511
  1677    0.39711
  1678   -0.02289
  1679   -0.05489
  1681   -0.01989
  1691    0.14411
  1697   -0.10589
  1699    0.09411
  1705    0.01411
  1711   -0.12589
  1713    0.04411
  1715    0.04411
  1716    0.01411
  1731    0.06411
  1738   -0.25589
  1741   -0.21589
  1745    0.39411
  1746   -0.13589
  1747   -0.10589
  1748    0.08411
  Name: RTdiff)
  </code></pre>
  
  <p>I would like to use it as input for the mtplotlib.pyplot.boxplot function. </p>
  
  <p>the error I get from <code>matplotlib.pyplot.boxplot(mydataframe)</code> is <code>ValueError: cannot set an array element with a sequence</code></p>
  
  <p>I tried to use <code>list(mydataframe)</code> instead of <code>mydataframe</code>. That fails with the same error.</p>
  
  <p>I also tried <code>matplotlib.pyplot.boxplot(np.fromiter(mydataframe, np.float))</code> - that fails with <code>ValueError: setting an array element with a sequence.</code></p>