将决策树直接转换为png

Question

我试图生成一个决策树，我想使用点可视化。生成的dotfile应转换为png格式。

虽然我可以在dos中使用

来完成最后一个转换步骤

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

后接DOS命令

dot -Tps graph.dot -o outfile.ps

直接在python中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，要让这个在pydot中运行，我必须写:

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