adding alternative syntax for sklearn 0.18

Author: rasbt

code/ch02/ch02.ipynb

@@ -0,0 +1,20 @@
+digraph Tree {
+node [shape=box] ;
+0 [label="petal width <= 0.75\nentropy = 1.5799\nsamples = 105\nvalue = [34, 32, 39]"] ;
+1 [label="entropy = 0.0\nsamples = 34\nvalue = [34, 0, 0]"] ;
+0 -> 1 [labeldistance=2.5, labelangle=45, headlabel="True"] ;
+2 [label="petal length <= 4.95\nentropy = 0.993\nsamples = 71\nvalue = [0, 32, 39]"] ;
+0 -> 2 [labeldistance=2.5, labelangle=-45, headlabel="False"] ;
+3 [label="petal width <= 1.65\nentropy = 0.4306\nsamples = 34\nvalue = [0, 31, 3]"] ;
+2 -> 3 ;
+4 [label="entropy = 0.0\nsamples = 30\nvalue = [0, 30, 0]"] ;
+3 -> 4 ;
+5 [label="entropy = 0.8113\nsamples = 4\nvalue = [0, 1, 3]"] ;
+3 -> 5 ;
+6 [label="petal length <= 5.05\nentropy = 0.1793\nsamples = 37\nvalue = [0, 1, 36]"] ;
+2 -> 6 ;
+7 [label="entropy = 0.8113\nsamples = 4\nvalue = [0, 1, 3]"] ;
+6 -> 7 ;
+8 [label="entropy = 0.0\nsamples = 33\nvalue = [0, 0, 33]"] ;
+6 -> 8 ;
+}