sklearn决策树图的Pydot错误

Question

我正在尝试使用 sklearn (http://scikit-learn.org/stable/modules/tree.html) 中的以下代码：

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")

我已经安装了 pydot==1.0.2，当我使用 Ipython notebook 运行这段代码时，出现以下错误。

InvocationException                       Traceback (most recent call last)
<ipython-input-22-18c25f6a061c> in <module>()
  4 tree.export_graphviz(clf, out_file=dot_data)
  5 graph = pydot.graph_from_dot_data(dot_data.getvalue())
----> 6 graph.write_pdf("iris.pdf")

 /Users/aj/anaconda/lib/python2.7/site-packages/pydot.pyc in <lambda>(path, f,     prog)
 1600             self.__setattr__(
 1601                 'write_'+frmt,
-> 1602                 lambda path, f=frmt, prog=self.prog : self.write(path,         format=f, prog=prog))
1603 
1604             f = self.__dict__['write_'+frmt]

/Users/aj/anaconda/lib/python2.7/site-packages/pydot.pyc in write(self, path, prog, format)
1694             dot_fd.write(self.to_string())
1695         else:
-> 1696             dot_fd.write(self.create(prog, format))
 1697         dot_fd.close()
 1698 

 /Users/aj/anaconda/lib/python2.7/site-packages/pydot.pyc in create(self, prog,  format)
 1794             raise InvocationException(
 1795                 'Program terminated with status: %d. stderr follows: %s'  % (
 -> 1796                     status, stderr_output) )
  1797         elif stderr_output:
  1798             print stderr_output

InvocationException: Program terminated with status: 1. stderr follows: Format: "pdf" not recognized. Use one of

不管我把它改成什么格式，它都给出了同样的错误。我运行在 Mac OS X Yosemite 上发布这个。

如有任何建议，我们将不胜感激。

Answer 1

其实这是graphviz的问题。显然，它需要 XQuartz 包（http://xquartz.macosforge.org/landing/），安装后一切正常。

sklearn决策树图的Pydot错误

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scikit-learn

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