《机器学习》周志华 习题答案4.3

　　原题，对西瓜数据集用决策树来进行划分，此处我只选取了西瓜的密度和含糖率这两个连续属性来进行划分，

#!/usr/bin/python
# -*- coding:utf-8 -*-
import numpy as np
import matplotlib.pyplot as plt
from matplotlib import colors
from sklearn.discriminant_analysis import QuadraticDiscriminantAnalysis

file1 = open(‘c:\quant\watermelon.csv‘,‘r‘)
data = [line.strip(‘\n‘).split(‘,‘) for line in file1]
X = [[float(raw[-3]), float(raw[-2])] for raw in data[1:]]
y = [1 if raw[-1]==‘1‘ else 0 for raw in data[1:]]
X = np.array(X)
y = np.array(y)
print y
#######################################################################以上是西瓜
from sklearn.datasets import load_iris
from sklearn import tree
from sklearn.externals.six import StringIO
import pydot
iris = load_iris()
clf = tree.DecisionTreeClassifier()
clf = clf.fit(iris.data, iris.target)

#with open("iris.dot", ‘w‘) as f:
#    f = tree.export_graphviz(clf, out_file=f)
filename = "iris.pdf"
dot_data = StringIO()
tree.export_graphviz(clf, out_file=dot_data)

graph = pydot.graph_from_dot_data(dot_data.getvalue())
print graph
graph.write_pdf(filename)

结果如下：