graph.write_pdf("iris.pdf") AttributeError: 'list' object has no attribute 'write_pdf'

Question

My code is follow the class of machine learning of google.The two code are same.I don't know why it show error.May be the type of variable is error.But google's code is same to me.Who has ever had this problem?

This is error

[0 1 2]
[0 1 2]
Traceback (most recent call last):
  File "/media/joyce/oreo/python/machine_learn/VisualizingADecisionTree.py", line 34, in <module>
    graph.write_pdf("iris.pdf")
AttributeError: 'list' object has no attribute 'write_pdf'
[Finished in 0.4s with exit code 1]
[shell_cmd: python -u "/media/joyce/oreo/python/machine_learn/VisualizingADecisionTree.py"]
[dir: /media/joyce/oreo/python/machine_learn]
[path: /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games]

This is code

import numpy as np
from sklearn.datasets import load_iris
from sklearn import tree

iris = load_iris()
test_idx = [0, 50, 100]

# training data
train_target = np.delete(iris.target, test_idx)
train_data = np.delete(iris.data, test_idx, axis=0)

# testing data
test_target = iris.target[test_idx]
test_data = iris.data[test_idx]

clf = tree.DecisionTreeClassifier()
clf.fit(train_data, train_target)

print test_target
print clf.predict(test_data) 

# viz code
from sklearn.externals.six import StringIO
import pydot
dot_data = StringIO()
tree.export_graphviz(clf,
        out_file=dot_data,
        feature_names=iris.feature_names,
        class_names=iris.target_names,
        filled=True, rounded=True,
        impurity=False)

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

Solution 1

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") 

Solution 2

I think you are using newer version of python. Please try with pydotplus.

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

This should do it.

Solution 3

I had exactly the same issue. Turned out that I hadn't installed graphviz. Once i did that it started to work.

Solution 4

@Alex Sokolov, for my case in window, i downloaded and install / unzip the following to a folder then setup the PATH in Windows environment variables. re-run the py code works for me. hope is helpful to you.

View more solutions

Comments

[乔守卿]

I just had a look.The graph is a list and it contain a pydot.Dot object.I use the pydot.Dot object call the function write_pdf("iris.pdf")，it also solve the question.

[programmer]

@乔守卿 What syntax did you use / how did you use pydot.Dot?

[Weizhou He]

@programmer The length of this list is actually 1. So, just graph[0].write_pdf. BTW, I guess the reason it returns a list is that there might be multiple trees in a single dot file.

[maheeka]

Thanks for the answer. Simple enough solution without having to go through the hassle of pydotplus

[questionto42standswithUkraine]

I could only install with pip install pydotplus, not with conda install pydotplus which caused InvalidArchiveError('Error with archive C:\\Users\\Admin\\Anaconda3\\pkgs\\openssl-1.1.1d-he774522_2‌​xysboxfd\\pkg-openss‌​l-1.1.1d-he774522_2.‌​tar.zst. You probably need to delete and re-download or re-create this file. Message from libarchive was:\n\nCould not unlink')