在scikit-learn中可视化决策树 [英] Visualizing decision tree in scikit-learn

问题描述

我正在尝试使用python中的scikit-learn设计一个简单的决策树（我正在Windows操作系统上使用Anaconda的Ipython Notebook和Python 2.7.3）并将其可视化如下：

I am trying to design a simple Decision Tree using scikit-learn in Python (I am using Anaconda's Ipython Notebook with Python 2.7.3 on Windows OS) and visualize it as follows:

from pandas import read_csv, DataFrame
from sklearn import tree
from os import system

data = read_csv('D:/training.csv')
Y = data.Y
X = data.ix[:,"X0":"X33"]

dtree = tree.DecisionTreeClassifier(criterion = "entropy")
dtree = dtree.fit(X, Y)

dotfile = open("D:/dtree2.dot", 'w')
dotfile = tree.export_graphviz(dtree, out_file = dotfile, feature_names = X.columns)
dotfile.close()
system("dot -Tpng D:.dot -o D:/dtree2.png")

但是，出现以下错误：

AttributeError: 'NoneType' object has no attribute 'close'

我使用以下博客文章作为参考：博客文章链接

I use the following blog post as reference: Blogpost link

以下stackoverflow问题似乎不起作用同样对我来说：问题

The following stackoverflow question doesn't seem to work for me as well: Question

有人可以帮助我如何在scikit-learn中可视化决策树吗？

Could someone help me with how to visualize the decision tree in scikit-learn?

推荐答案

sklearn.tree.export_graphviz 不返回任何内容，因此默认情况下返回无。

通过执行 dotfile = tree.export_graphviz（...），您将覆盖先前已分配给 dotfile 的打开文件对象，因此尝试关闭文件时出错（因为现在为 None ）。

By doing dotfile = tree.export_graphviz(...) you overwrite your open file object, which had been previously assigned to dotfile, so you get an error when you try to close the file (as it's now None).

要修复该文件，请将代码更改为

To fix it change your code to

...
dotfile = open("D:/dtree2.dot", 'w')
tree.export_graphviz(dtree, out_file = dotfile, feature_names = X.columns)
dotfile.close()
...

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