title: Color scatter plot points based on a value in third column?
body: <p>I am currently plotting a scatterplot based on two columns of data.  However, I would like to color the datapoints based on a class label that I have in a third column.</p>
  
  <p>The labels in my third column are either 1,2 or 3.  How would I color the scatter plot points based on the values in this third column?</p>
  
  <pre><code>plt.scatter(waterUsage['duration'],waterUsage['water_amount'])
  plt.xlabel('Duration (seconds)')
  plt.ylabel('Water (gallons)')
  </code></pre>