title: Iterating over an array of objects python
body: <p>I am trying to iterated over the array of matplotlib.axes.AxesSubplot retuned by pandas.DataFrame.hist to make each subhistogram logy. The following example code does not work</p>
  
  <pre><code>from pandas import DataFrame
  import numpy as np
  import matplotlib.pyplot as plt
  
  x = np.random.uniform(0, 100, size=1000)
  y = x *x  +  50*x*np.random.randn(1000)
  z = x * y  +  50*y*np.random.randn(1000)
  
  frame = DataFrame({'z' : z,'x' : x , 'y' : y})
  
  Histograms = frame.hist(bins=50)
  for axis in np.nditer(Histograms,"refs_ok"):
     axis.set_yscale("log", nonposy='clip')
  
  plt.show()
  </code></pre>