Python: NameError: global name 'dot_parser' is not defined

Question

Python is rather new to me.

I am trying to run the titanic machine learning example of the "Machine Learning in Python with Scikit" book. The classification with decision trees works fine (clf is defined properly) but if I want to visualize the decision tree (see code snippet below) I got the following error message (copied from IPython).

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-34-15b1b4a5d909> in <module>()
      3 dot_data = StringIO.StringIO()
      4 tree.export_graphviz(clf, out_file = dot_data, feature_names = ['PClass', 'AgeFill', 'Gender'])
----> 5 graph = pydot.graph_from_dot_data(dot_data.getvalue())
      6 graph.write_png('titanic.png')

C:\Users\885299\AppData\Local\Continuum\Anaconda32\lib\site-packages\pydot.pyc in graph_from_dot_data(data)

    218     """
    219 
--> 220     return dot_parser.parse_dot_data(data)
    221 
    222 
NameError: global name 'dot_parser' is not defined

Can somebody help me?

Code snippet that I used (similar to the book) was:

import pydot, StringIO

dot_data = StringIO.StringIO()
tree.export_graphviz(clf, out_file = dot_data, feature_names = ['Class', 'Age', 'Gender'])
graph = pydot.graph_from_dot_data(dot_data.getvalue())
graph.write_png('titanic.png')

from IPython.core.display import Image
Image(filename = 'titanic.png')

Answer 1

In case you're using Python 3, using pydotplus instead of pydot worked fine for me.

Here is the github repo