title: How to add a shared x-label and y-label to a plot created with pandas plot
body: <p><a href="https://stackoverflow.com/questions/42370857/how-to-share-axes-after-adding-subplots-via-add-subplot">One can create subplots easily from a dataframe using pandas:</a></p>
  
  <pre><code>import pandas as pd
  import matplotlib.pyplot as plt
  
  df = pd.DataFrame({'A': [0.3, 0.2, 0.5, 0.2], 'B': [0.1, 0.0, 0.3, 0.1], 'C': [0.2, 0.5, 0.0, 0.7], 'D': [0.6, 0.3, 0.4, 0.6]}, index=list('abcd'))
  
  ax = df.plot(kind="bar", subplots=True, layout=(2, 2), sharey=True, sharex=True, rot=0, fontsize=20)
  </code></pre>
  
  <p>How would one now add the x- and y-labels to the resulting plot? <a href="https://stackoverflow.com/questions/21487329/add-x-and-y-labels-to-a-pandas-plot">Here</a> it is explained for a single plot. So if I wanted to add labels to a particular subplot I could do:</p>
  
  <pre><code>ax[1][0].set_xlabel('my_general_xlabel')
  ax[0][0].set_ylabel('my_general_ylabel')
  plt.show()
  </code></pre>
  
  <p>That gives:</p>
  
  <p><a href="https://i.stack.imgur.com/M4nhy.png" rel="noreferrer"><img src="https://i.stack.imgur.com/M4nhy.png" alt="enter image description here"></a></p>
  
  <p>How would one add the labels so that they are centred and do not just refer to a one row/column?</p>