title: Annotate data points while plotting from Pandas DataFrame
body: <p>I would like to annotate the data points with their values next to the points on the plot. The examples I found only deal with x and y as vectors. However, I would like to do this for a pandas DataFrame that contains multiple columns. </p>
  
  <pre><code>ax = plt.figure().add_subplot(1, 1, 1)
  df.plot(ax = ax)
  plt.show()
  </code></pre>
  
  <p>What is the best way to annotate all the points for a multi-column DataFrame?</p>