title: parallel coordinates plot for continous data in pandas
body: <p>The parallel_coordinates function from pandas is very useful:</p>
  
  <pre><code>import pandas
  import matplotlib.pyplot as plt
  from pandas.tools.plotting import parallel_coordinates
  sampdata = read_csv('/usr/local/lib/python3.3/dist-packages/pandas/tests/data/iris.csv')
  parallel_coordinates(sampdata, 'Name')
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/s3z9R.png" alt="enter image description here"></p>
  
  <p>But when you have continous data, its behavior is not what you would expect:</p>
  
  <pre><code>mypos = np.random.randint(10, size=(100, 2))
  mydata = DataFrame(mypos, columns=['x', 'y'])
  myres = np.random.rand(100, 1)
  mydata['res'] = myres
  parallel_coordinates(mydata, 'res')
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/oMaLJ.png" alt="enter image description here"></p>
  
  <p>I would like to have the color of the lines to reflect the magnitude
  of the continuous variable, e.g. in a gradient from white to black,
  preferably also with the possibility of some transparency (alpha value),
  and with a color bar beside.</p>