title: Pandas scatter_matrix - plot categorical variables
body: <p>I am looking at the famous Titanic dataset from the Kaggle competition found here: <a href="http://www.kaggle.com/c/titanic-gettingStarted/data" rel="noreferrer">http://www.kaggle.com/c/titanic-gettingStarted/data</a></p>
  
  <p>I have loaded and processed the data using:</p>
  
  <pre><code># import required libraries
  import pandas as pd
  import matplotlib.pyplot as plt
  %matplotlib inline
  
  # load the data from the file
  df = pd.read_csv('./data/train.csv')
  
  # import the scatter_matrix functionality
  from pandas.tools.plotting import scatter_matrix
  
  # define colors list, to be used to plot survived either red (=0) or green (=1)
  colors=['red','green']
  
  # make a scatter plot
  scatter_matrix(df,figsize=[20,20],marker='x',c=df.Survived.apply(lambda x:colors[x]))
  
  df.info()
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/YWQal.png" alt="scatter_matrix from matplotlib"></p>
  
  <p>How can I add the categorical columns like Sex and Embarked to the plot?</p>