直接将决策树转换为png

Question

我正试图生成一个决策树，我想可视化使用点。生成的点文件应转换为png。

而我可以在dos中使用类似于

export_graphviz(dectree, out_file="graph.dot")

后跟DOS命令

dot -Tps graph.dot -o outfile.ps

在python中直接执行这些操作是行不通的，并且会生成一个错误

AttributeError: 'list' object has no attribute 'write_png'

这是我尝试过的程序代码：

from sklearn import tree  
import pydot
import StringIO

# Define training and target set for the classifier
train = [[1,2,3],[2,5,1],[2,1,7]]
target = [10,20,30]

# Initialize Classifier. Random values are initialized with always the same random seed of value 0 
# (allows reproducible results)
dectree = tree.DecisionTreeClassifier(random_state=0)
dectree.fit(train, target)

# Test classifier with other, unknown feature vector
test = [2,2,3]
predicted = dectree.predict(test)

dotfile = StringIO.StringIO()
tree.export_graphviz(dectree, out_file=dotfile)
graph=pydot.graph_from_dot_data(dotfile.getvalue())
graph.write_png("dtree.png")

我错过了什么？

Answer 1

我最终使用了pydotplus：

from sklearn import tree  
import pydotplus
import StringIO

# Define training and target set for the classifier
train = [[1,2,3],[2,5,1],[2,1,7]]
target = [10,20,30]

# Initialize Classifier. Random values are initialized with always the same random seed of value 0 
# (allows reproducible results)
dectree = tree.DecisionTreeClassifier(random_state=0)
dectree.fit(train, target)

# Test classifier with other, unknown feature vector
test = [2,2,3]
predicted = dectree.predict(test)

dotfile = StringIO.StringIO()
tree.export_graphviz(dectree, out_file=dotfile)
graph=pydotplus.graph_from_dot_data(dotfile.getvalue())
graph.write_png("dtree.png")

编辑：谢谢你的评论，要在pydot中运行，我必须写：

(graph,)=pydot.graph_from_dot_data(dotfile.getvalue())