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

我在可视化决策树，运行以下代码时报错：AttributeError: 'list' object has no attribute 'write_pdf'

我使用的是python3.4

from sklearn.externals.six import StringIO
import pydot
dot_data = StringIO()
tree.export_graphviz(clf, out_file=dot_data)
graph = pydot.graph_from_dot_data(dot_data.getvalue())
graph.write_pdf("iris.pdf") 

查阅资料后发现，原来我使用的是较新版本的python.可以采取如下两种解决方案：

• try with pydotplus：

import pydotplus
...
graph = pydotplus.graph_from_dot_data(dot_data.getvalue())
graph.write_pdf("iris.pdf")

• pydot.graph_from_dot_data() returns a list, so try:

graph = pydot.graph_from_dot_data(dot_data.getvalue())
graph[0].write_pdf("iris.pdf") 

REF.

[1]http://stackoverflow.com/questions/38176472/graph-write-pdfiris-pdf-attributeerror-list-object-has-no-attribute-writ