title: Plotting columns x and y of pandas dataframe with third column value determining the shape of the points
body: <p>I have this requirement. I have a sample data in a text file containing 3 attributes per line. Test1 score, Test2 score and pass or fail represented as 1 or 0. 
  example:-</p>
  
  <pre><code> Score1 Score2 Result
   35.00 55.00 0
   45.00 34.00 0
   50.00 75.00 0
   80.00 80.00 1
   55.00 85.00 1
   67.03 66.03 0
   ..
   ..
  </code></pre>
  
  <p>Now I am trying to plot Score1 against X-axis and Score2 against Y-axis , but I want to represent pass (1) as '+' while fail (0) as 'o' when I plot the points and in different colors ( for example '+' in green while 'o' in red)</p>
  
  <p>I wrote the code below as follows:-</p>
  
  <pre><code> pos=y[y==1]
   neg=y[y==0]
   get_ipython().magic('matplotlib inline')
  
   ax=X.plot(kind='scatter',x='Score1',y='Score2',s=pos*10,color='DarkGreen', label='Pass');        
   X.plot(kind='scatter', x='Score1', y='Score2', s=neg*200, color='Red',   label='Fail',ax=ax);
  </code></pre>
  
  <p>I am not sure if this right as I can only see the plot for pass result but not the color I am asking for while my fail result does not get plotted. 
  what am I doing wrong here ?</p>