title: Get positions of points in PathCollection created by scatter()
body: <p>If I create a scatterplot in matplotlib, how do I then get (or set) the coordinates of the points afterwards? I can access some properties of the collection, but I can't find out how to get the coordinates of the points themselves.</p>
  
  <p>I can get as far as;</p>
  
  <pre><code>import matplotlib.pyplot as plt
  
  fig = plt.figure()
  ax = fig.add_subplot(1,1,1)
  
  x = [0,1,2,3]
  y = [3,2,1,0]
  
  ax.scatter(x,y)
  
  ax.collections[0].properties()
  </code></pre>
  
  <p>Which lists off all the properties of the collection, but I don't recognize any of them as being the coordinates</p>