PyGraphViz agraph.layout() throws I0 error

问题:

After running the following Python code:

import pygraphviz as pgv
G=pgv.AGraph()
G.add_edge(1,2)
G.add_edge(2,3)
G.add_edge(3,4)
G.layout(prog='dot')
G.draw('1.png')

I got this trace in IDLE:

 File "<pyshell#7>", line 1, in <module>
   G.layout(prog='dot')
 File "C:\Python27\lib\site-packages\pygraphviz\agraph.py", line 1302, in layout
   data=self._run_prog(prog,' '.join([args,"-T",fmt]))
 File "C:\Python27\lib\site-packages\pygraphviz\agraph.py", line 1275, in _run_prog
   raise IOError("".join(errors))
 IOError: 'C:\Program' is not recognized as an internal or external command,
 operable program or batch file.

Please help, I am working on a course project. Information: Graphviz installed correctedly

回答1:

It looks like this is a bug with your version of PyGraphViz and Windows. I found this bug ticket describing it, but it was apparently fixed in 2011. It looks like they haven't actually released the update, but it should be in their SVN if you can switch to that.

If not, and you don't mind editing the source yourself, the actual fix they made is really trivial. Just find agraph.py, and change this line:

runprog=self._get_prog(prog) 

to

runprog=r'"%s"'%self._get_prog(prog)