Question :
When I run a very simple code with pydot
import pydot
graph = pydot.Dot(graph_type='graph')
for i in range(3):
edge = pydot.Edge("king", "lord%d" % i)
graph.add_edge(edge)
vassal_num = 0
for i in range(3):
for j in range(2):
edge = pydot.Edge("lord%d" % i, "vassal%d" % vassal_num)
graph.add_edge(edge)
vassal_num += 1
graph.write_png('example1_graph.png')
It prints me the error message:
Couldn't import dot_parser, loading of dot files will not be possible.
I’m using python 2.7.3
Answer #1:
Answer for pydot >= 1.1:
The incompatibility of (upstream) pydot has been fixed by 6dff94b3f1, and thus pydot >= 1.1 will be compatible with pyparsing >= 1.5.7.
Answer applicable to pydot <= 1.0.28:
For anyone else who comes across this, it is due to the changes in pyparsing from 1.x to the 2.x release.
To install pydot using pip, first install the older version of pyparsing:
pip install pyparsing==1.5.7
pip install pydot==1.0.28
If you did not install pyparsing using pip, but instead used setup.py, then have a look at this solution to uninstall the package. Thanks @qtips.
Answer #2:
There is a new package in the pip repo called pydot2 that functions correctly with pyparsing2. I couldn’t downgrade my packages because matplotlib depends on the newer pyparsing package.
Note: python2.7 from macports
Answer #3:
pydot used a private module variable (_noncomma) from pyparsing. The below diff fixes it to use for pyparsing 2.0.1:
diff --git a/dot_parser.py b/dot_parser.py
index dedd61a..138d152 100644
--- a/dot_parser.py
+++ b/dot_parser.py
@@ -25,8 +25,9 @@ from pyparsing import __version__ as pyparsing_version
from pyparsing import ( nestedExpr, Literal, CaselessLiteral, Word, Upcase, OneOrMore, ZeroOrMore,
Forward, NotAny, delimitedList, oneOf, Group, Optional, Combine, alphas, nums,
restOfLine, cStyleComment, nums, alphanums, printables, empty, quotedString,
- ParseException, ParseResults, CharsNotIn, _noncomma, dblQuotedString, QuotedString, ParserElement )
+ ParseException, ParseResults, CharsNotIn, dblQuotedString, QuotedString, ParserElement )
+_noncomma = "".join( [ c for c in printables if c != "," ] )
class P_AttrList:
Answer #4:
I forked the pydot repository [1], applied the Gabi Davar patch and some changes to support python-3. The package is available in the PyPI [2].
Cheers
Answer #5:
$ sudo pip uninstall pydot
$ sudo pip install pydot2
See the following link: http://infidea.net/troubleshooting-couldnt-import-dot_parser-loading-of-dot-files-will-not-be-possible/
Answer #6:
The solution was not to install pydot from somewhere, but “python-pydot” from official ubuntu repositories.
Answer #7:
There are now at least 2 more versions that appear to support PyParsing-2 and Python-3:
- PyDotPlus by Carlos Jenkins with a nice travis buildbot and fancy documentation. However you will need to change its folder name from
site-packagespydotplustosite-packagespydotfor it to work with existing programs that import pydot. - pydot3k by bmcorser. Sadly, did not work!
- prologic/pydot by James Mills linked to from the official pydot Google code page as …
a branch for Python 3 compatibility
- and here is a working link to David Villa’s pydot2 which works fine:
https://pypi.python.org/pypi/pydot2/1.0.32
Answer #8:
I had the problem again and my above solution did not work. If that is true for you and you are also using Anaconda on a Mac with El Capitan, try this:
conda install --channel https://conda.anaconda.org/RMG graphviz`
conda install --channel https://conda.anaconda.org/RMG pydot
